Alkylene oxide polymerization using a double metal cyanide catalyst complex and a magnesium, group 3-group 15 metal or lanthanide series metal compound

ABSTRACT

Alkylene oxide polymerizations are performed in the presence of a double metal cyanide polymerization catalyst and certain magnesium, Group 3-Group 15 metal or lanthanide series metal compounds. The presence of the magnesium, Group 3-Group 15 metal or lanthanide series metal compound provides several benefits including more rapid catalyst activation, faster polymerization rates and the reduction in the amount of ultra high molecular weight polymers that are formed. The catalyst mixture is unexpectedly useful in making polyethers having low equivalent weights.

This application claims priority from U.S. Provisional PatentApplication No. 61/427,331, filed 27 Dec. 2010.

This invention relates to a process for polymerizing an alkylene oxidein the presence of a double metal cyanide (DMC) polymerization catalyst.

Polyether monols and polyols are produced globally in large quantities.Polyether polyols are an important raw material for producingpolyurethanes. Polyether monols are used, for example, as surfactantsand industrial solvents, among other uses.

Polyether monols and polyols are produced by polymerizing an alkyleneoxide in the presence of an initiator compound. The initiator compoundhas one or more functional groups at which the alkylene oxide can reactto begin forming the polymer chains. The main functions of the initiatorcompound are to provide molecular weight control and to establish thenumber of hydroxyl groups that the polyether will have. The most widelyused initiator compounds are low molecular weight hydroxyl-containingcompounds, examples of which include, for example, glycerin,trimethylolpropane, ethylene glycol, diethylene glycol, propyleneglycol, dipropylene glycol, pentaerythritol, sorbitol and sucrose.

A catalyst is needed to obtain economical polymerization rates. The mostcommonly used catalysts are alkali metal hydroxides such as potassiumhydroxide and the so-called double metal cyanide (DMC) catalystcomplexes, of which zinc hexacyanocobaltate catalyst complexes are themost commercially important type.

The DMC catalyst complexes have certain advantages over the alkali metalhydroxides. Polyethers produced using alkali metal hydroxide catalystsmust be neutralized and purified to remove the catalyst residues. Thesesteps add expense and create waste streams. One advantage of using theDMC catalyst complexes is that the catalyst residues often can be leftin the product, unlike the case when alkali metal hydroxides are used asthe polymerization catalyst. This can result in lower production costs.And whereas alkali metal hydroxide catalysts can promote a side reactionthat forms unwanted monofunctional species, the DMC catalyst complexestend to form polyether products that are nearly devoid of those species.Unlike alkali metal hydroxide catalysts, DMC catalyst complexes producelow polydispersity polymers when the polymerization is performed in aback-mixed continuous main reactor. These advantages create strongincentives to use DMC catalyst complexes in commercial-scalepolymerization processes.

However, DMC catalysts have several problems that limit their use.

One problem with DMC complexes is that they sometimes activate slowly,or do not activate at all. The preparation of polyethers using the DMCcatalyst typically begins with a stage of the reaction known as thecatalyst induction period. During this stage of the reaction, the DMCcatalyst is believed to become converted in situ from an inactive forminto a highly active form that rapidly polymerizes the alkylene oxide aslong as it remains active. This catalyst induction period is typicallyan indeterminate period of time following the first introduction ofalkylene oxide to the reactor. It is common to introduce a small amountof alkylene oxide at the start of the polymerization process and thenwait unit the catalyst has become activated (as indicated, for example,by a drop in reactor pressure due to the consumption of the initialalkylene oxide charge) before continuing with the alkylene oxide feed.Such a process is disclosed in U.S. Pat. No. 5,844,070. Very little orno polymerization occurs until the catalyst has become activated, solong activation times have a direct negative impact on the productivityof the process. It is sometimes the case that the catalyst does notbecome activated at all. Such a failure of the catalyst to activatetypically will result in the abandonment of the attempt, and the processis started over again from the beginning. Therefore the activationprocess results in some loss of productivity under the bestcircumstances, and under the worst circumstances can cause a loss of theentire batch of starting mixture. The reduction or elimination of theinduction period at the start of the alkoxylation reaction is thereforeseen to be highly desirable.

A second problem has to do with the cost of the catalyst. Whereas alkalimetal hydroxide polymerization catalysts are quite inexpensive, DMCcatalyst complexes often cost hundreds of dollars per pound. Therefore,they have to be used in very small quantities so that catalyst costs donot become prohibitive. Catalyst concentrations below about 25 ppm(based on the weight of the polyether product) tend to be too small toprovide an economical polymerization rate. It would be desirable iflower amounts of the expensive DMC catalyst complex could be used.

A third problem is that DMC catalyst complexes perform poorly in thepresence of high concentrations of hydroxyl groups, and especially inthe presence of initiator compounds like glycerin that have hydroxylgroups in the 1,2- or 1,3-positions with respect to each other. Underthese conditions, the catalysts are difficult to activate, performsluggishly and often become deactivated before the polymerization iscompleted. This represents a significant limitation on the widespreadadoption of DMC catalysts.

For example, DMC catalysts are rarely if ever used commercially toproduce polyols that have hydroxyl equivalent weights (molecular weightdivided by the number of hydroxyl groups per molecule) below about 400,because the concentration of hydroxyl groups and initiator compounds ishigh enough during the polymerization process that the DMC catalyst doesnot perform well. This eliminates DMC catalyst complexes from being usedto produce a class of polyether polyols that have hydroxyl equivalentweights ranging from about 85 to 400, and especially from 125 to 300.This class of polyether polyols is produced in large quantities for usein producing rigid polyurethane foams and for the preparation ofcoatings, adhesives, sealants, and elastomer polymers.

DMC catalyst complexes have been used commercially to produce higherequivalent weight polyols, but even then the problem of catalystdeactivation increases process complexity and expense, and much of thepotential advantage of selecting DMC catalyst complexes instead ofalkali metal hydroxide catalysts is not realized.

The alkoxylation of low hydroxyl equivalent weight initiators cannotproceed directly from the initiator compound to the finished polyol,because the high concentration of hydroxyl groups and initiator compoundduring early stages of the polymerization severely inhibits initialcatalyst activation, and often results in failure of catalyst inductionor in premature deactivation of the catalyst early in the alkoxylationprocess. This problem is avoided by performing the early stages of thepolymerization in the presence of an alkali metal catalyst. This allowsan alkoxylated intermediate having a hydroxyl equivalent weight of about80 to 400 to be produced. This intermediate is recovered and theremainder of the polymerization is performed using the DMC catalyst.This approach requires the intermediate to be neutralized and purifiedto some extent (because the DMC catalyst is deactivated by strongbases), thus re-introducing costs which the DMC-catalyzed polymerizationis intended to avoid. Even when an intermediate is used in this manner,it is sometimes necessary to perform the polymerization in the presenceof a large amount of the higher equivalent weight final product. Thepresence of a large amount of product in the reaction mixture reducesthe concentration of hydroxyl groups, and helps to ameliorate theproblem of catalyst deactivation. Unfortunately, it reduces the amountof fresh product that can be prepared in a semi-batch reactor.

Solutions to the problem of catalyst deactivation in the presence ofhigh concentration of hydroxyl groups have been proposed, but none hasbeen found to be fully satisfactory, and none has led to thecommercial-scale production of low hydroxyl equivalent weight polyetherpolyols. U.S. Pat. No. 6,077,978 attributes the problem, at least inpart, to the presence of residual alkali in commercial-grade initiatorcompounds like glycerin, and describes adding small quantities of anacid to glycerin. US Published Patent Application No. 2008-021191 alsodescribes adding phosphoric acid into the polymerization process; inthis case the phosphoric acid is said to allow the polymerization toproceed from a low molecular weight starter in the presence of up to5000 ppm of water. These approaches have not been entirely satisfactory,since the residual salts produced by the neutralization can still hinderthe DMC catalyst. Long catalyst activation times are still commonlyseen, together with sluggish reactions and rapid deactivation of thecatalyst. These approaches also have not addressed the problem ofproducing low equivalent weight polyols using a DMC catalyst complex.

Another approach to improve the activity of DMC catalyst complexes is toadd quaternary ammonium halides into the alkoxylation reaction. See Leeet al., Polymer 48 (2007) 4361-4367.

A fourth problem is that DMC catalyst complexes often produce a smallamount of very high molecular weight (40,000+ g/mol) polymers. Thepresence of these polymers increases polyol viscosity and can alsoadversely affect the ability of the polyether polyols made with DMCcatalyst complexes to produce flexible polyurethane foam.

Certain metal alkoxides have been evaluated as alkylene oxidepolymerization catalysts. See, e.g., Osgan et al., J. Polym. Sci. 34(1959) 153-156; Miller et al., J. Polym. Sci., 34 (1959) 161-163;Jedlinski et al., Makromol. Chem. 180, 949-952 (1979). Aluminumisopropoxide was reported to polymerize propylene oxide over a period ofdays, when used in large amounts (1% by weight, or 10,000 ppm) in apolymerization conducted at 80° C. The polymerization tended to stopshort of completion, but the addition of zinc chloride was reported toallow the polymerization to proceed to completion, again using high (2%by weight) concentrations of the catalysts. Other metal alkoxides werereported as being even less effective catalysts.

Certain Lewis acids have been evaluated as alkylene oxide polymerizationcatalysts. The Lewis acids require essentially no activation time, butbecome deactivated rapidly and therefore cannot produce high molecularweight polymers or high conversions of alkylene oxide to polymer. Inaddition, poly(propylene oxide) polymers produced by Lewis acidcatalysis tend to have approximately 50% secondary hydroxyls and 50%primary hydroxyls.

Metal halides such as zinc chloride and aluminum trichloride have beenadded into DMC alkoxylation reactions in an attempt to eliminate theformation of a high molecular weight “tail” material that is often seenin those polymerizations. See, e.g., U.S. Pat. No. 6,028,230. However,the data in that patent suggests that these metal halides provide nobenefit in the absence of some small amount of water. Furthermore, onlyvery small amounts of the metal halide can be tolerated. U.S. Pat. No.6,028,230 reports that the DMC catalyst complex does not activate in thepresence of 30 ppm of zinc chloride (0.007 moles of zinc/gram of DMCcatalyst) in the absence of water, or in the presence of as little as 10ppm (0.0024 moles of zinc/gram of DMC catalyst complex) when as littleas 50 ppm of water is present.

There remains a desire to provide a viable process by which low hydroxylequivalent weight polyols can be prepared using a DMC catalyst complex,as well as a desire to provide a more effective process by which polyolscan be prepared by polymerizing an alkylene oxide in the presence ofhigh concentrations of low equivalent weight initiators using a DMCcatalyst complex.

There is also a desire to reduce the amount of DMC catalyst complex thatis needed to obtain fast polymerization rates at commercial scales.

There is also a desire to provide a way of reducing activation time of aDMC catalyst complex.

In addition, there is a desire to reduce the high molecular weight“tail” that is associated with DMC-catalyzed alkylene oxidepolymerizations.

This invention is in one aspect a method for producing a polyether monolor polyether polyol product, comprising polymerizing at least onealkylene oxide in the presence of a double metal cyanide catalystcomplex and a magnesium Group 3-Group 15 metal or lanthanide seriescompound in which a magnesium, Group 3-Group 15 metal or lanthanideseries metal is bonded to at least one alkoxide, aryloxy, carboxylate,acyl, pyrophosphate, phosphate, thiophosphate, dithiophosphate,phosphate ester, thiophosphate ester, amide, siloxide, hydride,carbamate or hydrocarbon anion, and wherein the magnesium, Group 3-Group15 or lanthanide series metal compound is devoid of halide anions.

In a particular aspect, the invention is a method for producing apolyether monol or polyether polyol product, comprising

(1) forming a catalyst mixture by combining (a) a double metal cyanidecatalyst complex and (b) a magnesium, Group 3-Group 15 metal orlanthanide series metal compound in which a magnesium, Group 3-Group 15metal or lanthanide series metal compound is bonded to at least onealkoxide, aryloxy, carboxylate, acyl, pyrophosphate, phosphate,thiophosphate, dithiophosphate, phosphate ester, thiophosphate ester,amide, siloxide, hydride, carbamate or hydrocarbon anion, and whereinthe magnesium, Group 3-Group 15 metal or lanthanide series metalcompound is devoid of halide anions,

(2) combining the catalyst mixture with at least one alkylene oxide andthen

(3) polymerizing the alkylene oxide.

The invention is also an alkylene oxide polymerization catalyst mixturecomprising a double metal cyanide catalyst complex and a magnesium,Group 3-Group 15 metal or lanthanide series metal compound in which amagnesium, Group 3-Group 15 metal or lanthanide series metal is bondedto at least one alkoxide, aryloxy, carboxylate, acyl, pyrophosphate,phosphate, thiophosphate, dithiophosphate, phosphate ester,thiophosphate ester, amide, siloxide, hydride, carbamate or hydrocarbonanion, and wherein the magnesium, Group 3-Group 15 metal or lanthanideseries compound is devoid of halide anions.

The invention is also a method for producing an alkylene oxidepolymerization catalyst mixture, comprising combining (a) a double metalcyanide catalyst complex and (b) a magnesium, Group 3-Group 15 metal orlanthanide series metal compound in which a magnesium, Group 3-Group 15metal or lanthanide series metal is bonded to at least one alkoxide,aryloxy, carboxylate, acyl, pyrophosphate, phosphate, thiophosphate,dithiophosphate, phosphate ester, thiophosphate ester, amide, siloxide,hydride, carbamate or hydrocarbon anion, and wherein the magnesium,Group 3-Group 15 metal compound or lanthanide series metal is devoid ofhalide anions.

The method of the invention offers several advantages.

In some embodiments of the invention, the presence of the magnesium,Group 3-Group 15 metal or lanthanide series metal compound (sometimesreferred to herein as “MG3-15LA compound”) has been found tosignificantly reduce the time required to activate the double metalcyanide catalyst complex, compared to when the DMC catalyst complex isused by itself (i.e., when the MG3-15LA compound is absent). Asdiscussed more fully below, the faster activation times in some casescorrelate to the selection of the anion portion of the MG3-15LAcompound. After the DMC catalyst complex has become activated, fasterpolymerization rates often are seen, compared to when the DMC catalystcomplex is used by itself (i.e., when the MG3-15LA compound is absent).As discussed more fully below, certain metals appear to provideespecially fast polymerization rates.

Very low concentrations of the DMC catalyst complex (well less than 25ppm of the DMC catalyst complex, based on the weight of the product)have in many cases been found to provide commercially acceptablepolymerization rates, particularly when the polyether product has ahydroxyl equivalent weight of 800 or more. The ability to perform thepolymerization using very low catalyst levels can lead to a verysignificant reduction in catalyst costs.

In addition, the DMC catalyst performs well even when the concentrationof hydroxyl groups is high during the polymerization process, activatingrapidly and providing good polymerization rates without deactivatingprematurely. Accordingly, the process is amenable to the production ofpolyether polyols that have hydroxyl equivalent weights in the range offrom 85 to 400 (especially from 125 to 300), as well as to theproduction of polyether polyols having hydroxyl equivalent weights offrom 401 to 5,000 or more. In addition, the process provides a method bywhich an alkylene oxide can be polymerized onto a low equivalent weightinitiator compound such as glycerin or sorbitol.

The process of the invention is very well adapted for continuouspolymerizations in which the initiator compound and the alkylene oxideare continuously added to the polymerization. It also is suitable forbatch or semi-batch polymerization processes.

Yet another advantage is that the process of this invention tends toproduce polyether polyol products that have very small levels ofultra-high molecular weight (40,000+g/mol) materials.

Suitable double metal cyanide catalysts include those described, forexample, in U.S. Pat. Nos. 3,278,457, 3,278,458, 3,278,459, 3,404,109,3,427,256, 3,427,334, 3,427,335 and 5,470,813. Some suitable DMCcatalysts can be represented by the formulaM_(b)[M¹(CN)_(r)(X)_(t)]_(c)[M²(X)₆]_(d).nM³ _(x)A_(y)wherein M and M³ are each metals; M¹ is a transition metal differentfrom M, each X represents a group other than cyanide that coordinateswith the M¹ ion; M² is a transition metal; A represents an anion; b, cand d are numbers that reflect an electrostatically neutral complex; ris from 4 to 6; t is from 0 to 2; x and y are integers that balance thecharges in the metal salt M³ _(x)A_(y), and n is zero or a positiveinteger. The foregoing formula does not reflect the presence of neutralcomplexing agents such as t-butanol which are often present in the DMCcatalyst complex.

M and M³ each are preferably a metal ion independently selected from thegroup consisting of Zn²⁺, Fe²⁺, Co⁺²⁺, Ni²⁺, Mo⁴⁺, Mo⁶⁺, Al⁺³⁺, V⁴⁺,V⁵⁺, Sr²⁺, W⁴⁺, W⁶⁺, Mn²⁺, Sn²⁺, Sn⁴⁺, Pb²⁺, Cu²⁺, La³⁺ and Cr³⁺, withZn²⁺ being preferred.

M¹ and M² are preferably Fe³⁺, Fe²⁺, Co³⁺, Co²⁺, Cr²⁺, Cr³⁺, Mn²⁺, Mn³⁺,Ir³⁺, Ni²⁺, Rh³⁺, Ru²⁺, V⁴⁺, V⁵⁺, Ni²⁺, Pd²⁺, and Pt²⁺. Among theforegoing, those in the plus-three oxidation state are more preferred asthe M¹ and M² metal. Co⁺³ and Fe⁺³ are even more preferred and Co⁺³ ismost preferred.

Suitable anions A include but are not limited to halides such aschloride, bromide and iodide, nitrate, sulfate, carbonate, cyanide,oxalate, thiocyanate, isocyanate, perchlorate, isothiocyanate, analkanesulfonate such as methanesulfonate, an arylenesulfonate such asp-toluenesulfonate, trifluoromethanesulfonate (triflate) and a C₁₋₄carboxylate. Chloride ion is especially preferred.

r is preferably 4, 5 or 6, preferably 4 or 6, and most preferably 6; tis preferably 0 or 1, most preferably 0. In most cases, r+t will equalsix.

A suitable type of DMC catalyst is a zinc hexacyanocobaltate catalystcomplex as described, for example, in any of U.S. Pat. Nos. 3,278,457,3,278,458, 3,278,459, 3,404,109, 3,427,256, 3,427,334, 3,427,335 and5,470,813. An especially preferred type of DMC catalyst is complexedwith t-butanol.

The MG3-15LA compound is a separately added ingredient, which is notpresent during the preparation (i.e., the precipitation step) of the DMCcatalyst complex. The mechanism by which the MG3-15LA compound providesbenefits to the polymerization is not fully understood. Although theinvention is not bound by any theory, it is possible that some reactionor other interaction between this compound and the DMC catalyst complextakes place.

The MG3-15LA compound contains a magnesium, Group 3-Group 15 metal orlanthanide series metal ion bonded to at least one alkoxide, aryloxy,carboxylate, acyl, pyrophosphate, phosphate, thiophosphate,dithiophosphate, phosphate ester, thiophosphate ester, amide, siloxide,hydride, carbamate or hydrocarbon anion. The MG3-15LA compound is devoidof halide anions.

By “alkoxide ion” it is meant a species having the form ⁻O—R, where R isan alkyl group or substituted alkyl group, and which is the conjugatebase, after removal of a hydroxyl hydrogen, of an alcohol compoundhaving the form HO—R. These alcohols typically have pKa values in therange of 13 to 25 or greater. The alkoxide ion in some embodiments maycontain from one to 20, more preferably from one to 6 and still morepreferably from 2 to 6 carbon atoms. The alkyl group or substitutedalkyl group may be linear, branched and/or cyclic. Examples of suitablesubstituents include, for example, additional hydroxyl groups (which maybe in the alkoxide form), ether groups, carbonyl groups, ester groups,urethane groups, carbonate groups, silyl groups, aromatic groups such asphenyl and alkyl-substituted phenyl, halogen, and the like. Examples ofsuch alkoxide ions include methoxide, ethoxide, isopropoxide,n-propoxide, n-butoxide, sec-butoxide, t-butoxide, benzyloxy, and thelike. In other embodiments, the R group may contain one or more hydroxylgroups and/or may contain one or more ether linkages. An alkoxide ionmay correspond to the residue (after removal of one or more hydroxylhydrogens) of an initiator compound that is present in thepolymerization, such as those initiator compounds described below. Thealkoxide ion may be an alkoxide formed by removing one or more hydroxylhydrogens from a polyether monol or polyether polyol; such an alkoxidein some embodiments corresponds to a residue, after removal of one ormore hydroxyl hydrogen atoms, of the polyether monol or polyether polyolproduct that is obtained from the alkoxylation reaction, or of apolyether having a molecular weight intermediate to that of theinitiator compound and the product of the alkoxylation reaction.

By “aryloxy anion” it is meant a species having the form ⁻O—Ar, where Aris an aromatic group or substituted group, and which corresponds, afterremoval of a hydroxyl hydrogen, to a phenolic compound having the formHO—Ar. These phenolic compounds may have a pKa of, for example, fromabout 9 to about 12. Examples of such aryloxy anions include phenoxideand ring-substituted phenoxides, wherein the ring-substituents include,for example, alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl, alkoxyl andthe like. The ring-substituent(s), if present, may be in one or more ofthe ortho-, para- and/or meta-positions relative to the phenolic group.The phenoxide anions also include the conjugate bases of polyphenoliccompounds such as bisphenol A, bisphenol F and various other bisphenols,1,1,1-tris(hydroxyphenyl)ethane, and fused ring aromatics such as1-naphthol and the like.

A carboxylate anion preferably contains from one to 24, more preferablyfrom 2 to 18 and still more preferably from 2 to 12 carbon atoms. It maybe aliphatic or aromatic. An aliphatic carboxylic acid may containsubstituent groups such as hydroxyl groups (which may be in the alkoxideform), ether groups, carbonyl groups, ester groups, urethane groups,carbonate groups, silyl groups, aromatic groups such as phenyl andalkyl-substituted phenyl, halogen, and the like. Examples of aliphaticcarboxylate anions include formate, acetate, propionate, butyrate,2-ethylhexanoate, n-octoate, decanoate, laurate and other alkanoates andhalogen-substituted alkanoates such as 2,2,2-trifluoroacetate,2-fluoroacetate, 2,2-difluoroacetate, 2-chloroacetate,2,2,2-trichloroacetate and the like. Aromatic carboxylates includebenzoate, alkyl-substituted benzoate, halo-substituted benzoate,4-cyanobenzoate, 4-trifluoromethylbenzoate, salicylate,3,5-di-t-butylsalicylate, subsalicylate, and the like. In someembodiments, such a carboxylate ion may be the conjugate base of acarboxylic acid having a pKa from 1 to 6, preferably from 3 to 5.

By “acyl anion”, it is meant a conjugate base of a compound containing acarbonyl group including, for example, an aldehyde, ketone, carbonate,ester or similar compound that has an enol form. Among these areß-diketo compounds, such as acetoacetonate, butylacetoacetonate and thelike.

Phosphate ester anions include those having the formula ⁻O—P(O)(OR¹)₂,wherein R is alkyl, substituted alkyl, phenyl or substituted phenyl.Thiophosphate esters have the corresponding structure in which one ormore of the oxygens are replaced with sulfur.

By “amide anion”, it is meant an ion in which a nitrogen atom bears anegative charge. The amide ion generally takes the form ⁻N(R²)₂, whereinthe R² groups are independently hydrogen, alkyl, aryl, trialkylsilyl,triarylsilyl and the like. The alkyl groups may be linear, branched orcyclic. Any of these groups may contain substituents such as ether orhydroxyl. The two R² groups may together form a ring structure, whichring structure may be unsaturated and/or contain one or more heteroatoms(in addition to the amide nitrogen) in the ring.

Hydrocarbyl anions include aliphatic, cycloaliphatic and/or aromaticanions wherein the negative charge resides on a carbon atom. Thehydrocarbyl anions are conjugate bases of hydrocarbons that typicallyhave pKa values in excess of 30. The hydrocarbyl anions may also containinert substituents. Of the aromatic hydrocarbyl anions, phenyl groupsand substituted phenyl groups are preferred. Aliphatic hydrocarbylanions are preferably alkyl groups, which more preferably contain from 1to 12, more preferably from 2 to 8 carbon atoms. Methyl, ethyl,n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, cyclopentadienyl andt-butyl anions are all useful, for example.

Preferred anions are the conjugate base of a compound having a pKa of atleast 1.5, preferably at least 2.5, still more preferably at least 3.0.The pKa of the conjugate acid has been found to relate to the timerequired to activate the DMC catalyst complex in a polymerizationprocess of this invention. It has been found that shorter activationtimes are generally seen when the anions correspond to the conjugatebase of a compound having a pKa of at least 9, preferably at least 12,more preferably at least 13. The anion may be the conjugate base of acompound having any higher pKa, such as up to 60 or higher. Anionscorresponding to the conjugate base of a compound having a pKa of lessthan 9, especially less than 5, often have been found to lead to longeractivation times. Therefore, especially preferred anions are alkoxide,aryloxy, amide, and hydrocarbyl anions which are the conjugate base of acompound having a pKa of at least 9, more preferably at least 12 andstill more preferably at least 13, up to 60 or greater.

The Group 3-Group 15 metals are metals falling within any of groups IIIthrough 15, inclusive, of the 2010 IUPAC periodic table of the elements.The metal may be, for example, scandium, yttrium, lanthanum, titanium,zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum,tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, rhodium,iridium, nickel, palladium, platinum, copper, silver, gold, zinc,cadmium, mercury, aluminum, gallium, indium, tellurium, germanium, tin,lead, antimony, bismuth, and the lanthanide series metals includingthose having atomic numbers from 58 (cerium) to 71 (lutetium),inclusive.

Preferred metals include those in Groups 3, 4, 5, 12, 13 and 14. Amongthese, scandium, yttrium, hafnium, titanium, zirconium, niobium,vanadium, zinc, aluminum, gallium, indium and tin are more preferred, asthese metals tend to provide fast polymerization rates and/or allow verysmall quantities of the DMC catalyst to be present. Aluminum, zinc,hafnium, gallium, indium, tin, titanium and zirconium are especiallypreferred.

Among the suitable MG3-15LA compounds are those corresponding to eitherof the formula M⁴A¹ _(z) and M⁴(O)A¹ _(z), wherein M⁴ is the magnesium,Group 3-Group 15 or lanthanide series metal and each A¹ is independentlyan anion as described before and z is a number of at least one whichreflects an electrostatically neutral compound, provided that any two ormore A¹ groups may together form a polyvalent group. Each A¹ preferablyis independently an alkoxide, aryloxy anion, amide anion or hydrocarbylanion that is the conjugate base of a compound having a pKa of at least9, more preferably at least 12 and still more preferably at least 13. Asbefore, any A¹ may be an alkoxide anion which is the conjugate base ofan initiator compound or a polyether monol or polyether polyol,including the polyether monol or polyether polyol product that isobtained from the alkoxylation reaction or a polyether having amolecular weight intermediate to that of the initiator compound and theproduct of the alkoxylation reaction.

The MG3-15LA compound is preferably devoid of anions that are conjugatebases of inorganic acids such as sulfate, sulfite, persulfate, nitrate,nitrite, chlorate, perchlorate, hypochlorite, carbonate, chromate, andthe like; sulfonate anions such as trifluoromethylsulfonate and methylsulfonate; and hydroxide ions.

Examples of suitable MG3-15LA compounds include but are not limited to:

a) magnesium alkyls such as diethyl magnesium, dibutyl magnesium,butylethyl magnesium, dibenzyl magnesium and the like; magnesiumalkoxides such as magnesium methoxide, magnesium ethoxide, magnesiumisopropoxide, magnesium t-butoxide, magnesium sec-butoxide and the like;magnesium aryloxides such as magnesium phenoxide, and magnesiumphenoxides in which one or more of the phenoxide groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like; magnesium carboxylates such as magnesium formate,magnesium acetate, magnesium propionate, magnesium 2-ethylhexanoate,magnesium benzoate, magnesium benzoates in which one or more of thebenzoate groups is ring-substituted with alkyl, CF₃, cyano, COCH₃,halogen, hydroxyl, alkoxyl and the like, magnesium salicylate, magnesium3,5-di-t-butyl salicylate; magnesium amides such as magnesiumdimethylamide, magnesium diethylamide, magnesium diphenylamide,magnesium bis(trimethylsilyl)amide and the like; magnesiumacetylacetonate and magnesium t-butylacetylacetonate.

b) scandium alkoxides such as scandium methoxide, scandium ethoxide,scandium isopropoxide, scandium t-butoxide, scandium sec-butoxide andthe like; scandium aryloxides such as scandium phenoxide and scandiumphenoxides in which one or more of the phenoxide groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like; scandium carboxylates such as scandium formate,scandium acetate, scandium propionate, scandium 2-ethylhexanoate,scandium benzoate, scandium benzoates in which one or more of thebenzoate groups is ring-substituted with alkyl, CF₃, cyano, COCH₃,halogen, hydroxyl, alkoxyl and the like; scandium salicylate; scandiumacetylacetonate and scandium t-butylacetylacetonate.

c) yttrium alkoxides such as yttrium methoxide, yttrium ethoxide,yttrium isopropoxide, yttrium t-butoxide, yttrium sec-butoxide and thelike; yttrium aryloxides such as yttrium phenoxide, and yttriumphenoxides in which one or more of the phenoxide groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like; yttrium carboxylates such as yttrium formate,yttrium acetate, yttrium propionate, yttrium 2-ethylhexanoate, yttriumbenzoate, yttrium benzoates in which one or more of the benzoate groupsis ring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like, yttrium salicylate, yttrium 3,5-di-t-butylsalicylate; yttrium amides such as yttrium dimethylamide, yttriumdiethylamide, yttrium diphenylamide, yttrium bis(trimethylsilyl)amideand the like; yttrium acetylacetonate and yttriumt-butylacetylacetonate.

d) hafnium alkyls such as such as tetraethyl hafnium, tetrabutylhafnium, tetrabenzyl hafnium and the like; hafnium alkoxides such ashafnium tetramethoxide, hafnium tetraethoxide, hafniumtetraisopropoxide, hafnium tetra-t-butoxide, hafnium tetra-sec-butoxideand the like; hafnium aryloxides such as hafnium phenoxide and hafniumphenoxides in which one or more of the phenoxide groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like; hafnium carboxylates such as hafnium formate,hafnium acetate, hafnium propionate, hafnium 2-ethylhexanoate, hafniumbenzoate, hafnium benzoates in which one or more of the benzoate groupsis ring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like, hafnium salicylate, hafnium 3,5-di-t-butylsalicylate; hafnium amides such as hafnium tetra(dimethylamide), hafniumtetra(diethylamide), hafnium tetra(diphenylamide), hafniumtetra((bistrimethylsilyl)amide); hafnium acetylacetonate and hafniumt-butylacetylacetonate;

e) titanium alkyls such as such as tetraethyl titanium, tetrabenzyltitanium and the like; titanium alkoxides such as titaniumtetramethoxide, titanium tetraethoxide, titanium tetraisopropoxide,titanium tetra-t-butoxide, titanium tetra-sec-butoxide and the like;titanium aryloxides such as titanium phenoxide and titanium phenoxidesin which one or more of the phenoxide groups is ring-substituted withalkyl, CF₃, cyano, COCH₃, halogen, hydroxyl, alkoxyl and the like;titanium carboxylates such as titanium formate, titanium acetate,titanium propionate, titanium 2-ethylhexanoate, titanium benzoate,titanium benzoates in which one or more of the benzoate groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like, titanium salicylate, titanium 3,5-di-t-butylsalicylate; titanium amides such as titanium tetra(dimethylamide),titanium tetra(diethylamide, titanium tetra(diphenylamide), titaniumtetra((bistrimethylsilyl)amide); titanium acetylacetonate and titaniumt-butylacetylacetonate;

f) zirconium alkyls such as such as tetraethyl zirconium, tetrabutylzirconium, tetrabenzyl zirconium and the like; zirconium alkoxides suchas zirconium tetramethoxide, zirconium tetraethoxide, zirconiumtetraisopropoxide, zirconium tetra-t-butoxide, zirconiumtetra-sec-butoxide and the like; zirconium aryloxides such as zirconiumphenoxide and zirconium phenoxides in which one or more of the phenoxidegroups is ring-substituted with alkyl, CF₃, cyano, COCH₃, halogen,hydroxyl, alkoxyl and the like; zirconium carboxylates such as zirconiumformate, zirconium acetate, zirconium propionate, zirconium2-ethylhexanoate, zirconium benzoate, zirconium benzoates in which oneor more of the benzoate groups is ring-substituted with alkyl, CF₃,cyano, COCH₃, halogen, hydroxyl, alkoxyl and the like, zirconiumsalicylate, zirconium 3,5-di-t-butyl salicylate; zirconium amides suchas zirconium tetra(dimethylamide), zirconium tetra(diethylamide,zirconium tetra(diphenylamide), zirconiumtetra((bistrimethylsilyl)amide); zirconium acetylacetonate and zirconiumt-butylacetylacetonate;

g) vanadium alkoxides such as vanadium methoxide, vanadium ethoxide,vanadium isopropoxide, vanadium t-butoxide, vanadium sec-butoxide andthe like; vanadium oxo tris(alkoxides) such as vanadium oxotris(methoxide), vanadium oxo tris(ethoxide), vanadium oxotris(isopropoxide), vanadium oxo tris(t-butoxide), vanadium oxotris(sec-butoxide) and the like; vanadium aryloxides such as vanadiumphenoxide and vanadium phenoxides in which one or more of the phenoxidegroups is ring-substituted with alkyl, CF₃, cyano, COCH₃, halogen,hydroxyl, alkoxyl and the like; vanadium carboxylates such as vanadiumformate, vanadium acetate, vanadium propionate, vanadium2-ethylhexanoate, vanadium benzoate, vanadium benzoates in which one ormore of the benzoate groups is ring-substituted with alkyl, CF₃, cyano,COCH₃, halogen, hydroxyl, alkoxyl and the like, vanadium salicylate,vanadium 3,5-di-t-butyl salicylate; vanadium tris(acetylacetonate) andvanadium tris(t-butylacetylacetonate); vanadium oxobis(acetylacetonate);

h) zinc alkyls such as such as dimethyl zinc, diethyl zinc, dibutylzinc, dibenzyl zinc and the like; alkyl zinc alkoxides such as ethylzinc isopropoxide; zinc alkoxides such as zinc methoxide, zinc ethoxide,zinc isopropoxide, zinc t-butoxide, zinc sec-butoxide and the like; zincaryloxides such as zinc phenoxide and zinc phenoxides in which one ormore of the phenoxide groups is ring-substituted with alkyl, CF₃, cyano,COCH₃, halogen, hydroxyl, alkoxyl and the like; zinc carboxylates suchas zinc formate, zinc acetate, zinc propionate, zinc 2-ethylhexanoate,zinc benzoate, zinc benzoates in which one or more of the benzoategroups is ring-substituted with alkyl, CF₃, cyano, COCH₃, halogen,hydroxyl, alkoxyl and the like, zinc salicylate, zinc 3,5-di-t-butylsalicylate; zinc amides such as zinc dimethylamide, zinc diethylamide,zinc diphenylamide, zinc (bistrimethylsilyl)amide; zinc acetylacetonateand zinc t-butylacetylacetonate;

i) trialkyl aluminum compounds such as trimethylaluminum, triethylaluminum, tributyl aluminum, tribenzylaluminum and the like; aluminumalkoxides such as aluminum trimethoxide, aluminum triethoxide, aluminumtriisopropoxide, aluminum tri-t-butoxide, aluminum tri-sec-butoxide andthe like; aluminum aryloxides such as aluminum phenoxide and aluminumphenoxides in which one or more of the phenoxide groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like; aluminum carboxylates such as aluminum formate,aluminum acetate, aluminum propionate, aluminum 2-ethylhexanoate,aluminum benzoate, aluminum benzoates in which one or more of thebenzoate groups is ring-substituted with alkyl, CF₃, cyano, COCH₃,halogen, hydroxyl, alkoxyl and the like, aluminum salicylate, aluminum3,5-di-t-butyl salicylate; aluminum amides such as aluminumtris(dimethylamide), aluminum tris(diethylamide), aluminumtris(diphenylamide), aluminum tris(di(trimethylsilyl)amide) and thelike; aluminum acetylacetonate; aluminum t-butylacetylacetonate; andalkylaluminum oxides and alkoxides such as diethylaluminum ethoxide,dimethylaluminum ethoxide, diethylaluminum isopropoxide,dimethylaluminum isopropoxide, methyl aluminoxane,tetraethyldialuminoxane and the like;

j) trialkyl gallium compounds such as trimethylgallium, triethylgallium, tributyl gallium, tribenzylgallium and the like; galliumalkoxides such as gallium trimethoxide, gallium triethoxide, galliumtriisopropoxide, gallium tri-t-butoxide, gallium tri-sec-butoxide andthe like; gallium aryloxides such as gallium phenoxide and galliumphenoxides in which one or more of the phenoxide groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like; gallium carboxylates such as gallium formate,gallium acetate, gallium propionate, gallium 2-ethylhexanoate, galliumbenzoate, gallium benzoates in which one or more of the benzoate groupsis ring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like, gallium salicylate, gallium 3,5-di-t-butylsalicylate; gallium amides such as gallium tris(dimethylamide), galliumtris(diethylamide), gallium tris(diphenylamide), galliumtris(di(trimethylsilyl)amide) and the like; gallium acetylacetonate;gallium t-butylacetylacetonate; and alkylgallium alkoxides such asdiethylgallium ethoxide, dimethylgallium ethoxide, diethylgalliumisopropoxide and dimethylgallium isopropoxide;

k) trialkyl indium compounds like trimethyl indium; indium alkoxidessuch as indium methoxide, indium ethoxide, indium isopropoxide, indiumt-butoxide, indium sec-butoxide and the like; indium aryloxides such asindium phenoxide and indium phenoxides in which one or more of thephenoxide groups is ring-substituted with alkyl, CF₃, cyano, COCH₃,halogen, hydroxyl, alkoxyl and the like; indium carboxylates such asindium formate, indium acetate, indium propionate, indium2-ethylhexanoate, indium benzoate, indium benzoates in which one or moreof the benzoate groups is ring-substituted with alkyl, CF₃, cyano,COCH₃, halogen, hydroxyl, alkoxyl and the like, indium salicylate,indium 3,5-di-t-butyl salicylate; indium acetylacetonate; and indiumt-butylacetylacetonate; and

l) stannous phosphate; stannous pyrophosphate, stannous alkoxides suchas stannous methoxide, stannous ethoxide, stannous isopropoxide,stannous t-butoxide, stannous sec-butoxide and the like; stannousaryloxides such as stannous phenoxide and stannous phenoxides in whichone or more of the phenoxide groups is ring-substituted with alkyl, CF₃,cyano, COCH₃, halogen, hydroxyl, alkoxyl and the like; stannouscarboxylates such as stannous formate, stannous acetate, stannouspropionate, stannous 2-ethylhexanoate, stannous benzoate, stannousbenzoates in which one or more of the benzoate groups isring-substituted with alkyl, CF₃, cyano, COCH₃, halogen, hydroxyl,alkoxyl and the like, stannous salicylate, stannous 3,5-di-t-butylsalicylate; stannous acetylacetonate; and stannoust-butylacetylacetonate.

In addition to the foregoing, other suitable MG3-15LA compounds includemagnesium, Group 3-Group 15 or lanthanide series metal alkoxides whereinone or more of the alkoxide group(s) are the conjugate base, afterremoval of one or more hydroxyl hydrogen atoms, from (1) an initiatorcompound as described below, (2) a polyether monol or polyether polyolproduct of the polymerization reaction or (3) a polyether having amolecular weight intermediate to the initiator and the polyether monolor polyether polyol product of the polymerization.

If desired, mixtures of two or more of the foregoing MG3-15LA compoundsmay be used.

The alkylene oxide may be, for example, ethylene oxide, 1,2-propyleneoxide, 2,3-propylene oxide, 1,2-butane oxide, 2-methyl-1,2-butaneoxide,2,3-butane oxide, tetrahydrofuran, epichlorohydrin, hexane oxide,styrene oxide, divinylbenzene dioxide, a glycidyl ether such asBisphenol A diglycidyl ether, or other polymerizable oxirane. Thepreferred alkylene oxide by far is 1,2-propylene oxide, or a mixture ofat least 50% (preferably at least 80%) by weight propylene oxide and upto 50% (preferably up to 20%) ethylene oxide.

The polymerization is preferably performed in the presence of ahydroxyl-containing initiator compound. The hydroxyl-containinginitiator compound is any organic compound that is to be alkoxylated inthe polymerization reaction. It contains 1 or more hydroxyl groups,preferably 2 or more hydroxyl groups. It may contain as many as 12 ormore hydroxyl groups. Preferred initiators for producing polyols for usein polyurethane applications will have from 2 to 8 hydroxyl groups permolecule. In some embodiments, the initiator compound will have from 2to 4 or from 2 to 3 hydroxyl groups. In other embodiments, the initiatorcompound will have from 4 to 8 or from 4 to 6 hydroxyl groups. Theinitiator compound may have at least two hydroxyl groups that are in the1,2- or 1,3-positions with respect to each other (taking the carbon atomto which one of the hydroxyl groups is bonded as the “1” position).Mixtures of initiator compounds can be used.

The initiator compound will have a hydroxyl equivalent weight less thanthat of the polyether product. It may have a hydroxyl equivalent weightof from 30 to 500 or more. In some embodiments, the initiator compoundhas a hydroxyl equivalent weight of from 30 to 125, especially from 30to 100.

Suitable initiators include but are not limited to ethylene glycol,diethylene glycol, triethylene glycol, propylene glycol, dipropyleneglycol, tripropylene glycol, 1,4-butane diol, 1,6-hexane diol,1,8-octane diol, cyclohexane dimethanol, glycerin, trimethylolpropane,trimethylolethane, pentaerythritol, sorbitol and sucrose, phenol andpolyphenolic initiators such as bisphenol A or1,1,1-tris(hydroxyphenyl)ethane and the like, as well as alkoxylates(especially ethoxylates and/or propoxylates) of any of these that have ahydroxyl equivalent weight less than that of the product of thepolymerization, preferably up to 500, more preferably up to 250, evenmore preferably up to 125, and still more preferably up to 100.

The initiator may be neutralized with or contain a small amount of anacid, particularly if the initiator is prepared in the presence of abase (as is often the case with glycerin). If an acid is present, it maybe present in an amount of from about 10 to 100 ppm, based on the weightof the initiator, as described in U.S. Pat. No. 6,077,978.Alternatively, the acid may be used in somewhat larger amounts, such asfrom 100 to 1000 ppm, again based on the weight of the initiator, asdescribed in US Published Patent Application No. 2005-0209438. The acidmay be added to the initiator before or after the initiator is combinedwith the DMC catalyst and the MG3-15LA compound.

In the present invention, an alkylene oxide is polymerized in thepresence of the DMC catalyst complex and the MG3-15LA compound, or acatalyst mixture formed by combining the DMC catalyst complex and theMG3-15LA compound. In some embodiments, enough of the MG3-15LA compoundis present to provide at least 0.0005 moles of the magnesium, group3-group 15 metal or lanthanide series metal per gram of the DMC catalystcomplex. A preferred amount is enough to provide at least 0.0025 or atleast 0.005 moles of the magnesium, group 3-group 15 metal or lanthanideseries metal per gram of the DMC catalyst complex. It is generally notnecessary to provide more than 10 moles of magnesium, group 3-group 15metal or lanthanide series metal compound per gram of the DMC catalystcomplex. A preferred upper limit is enough to provide up to 1 mole, upto 0.5 moles or up to 0.25 moles of magnesium, group 3-group 15 metal orlanthanide series metal per gram of DMC catalyst complex. The foregoingamounts do not include any amounts of metals that are included withinthe DMC catalyst complex.

In some embodiments, the polymerization is performed by forming acatalyst mixture by combining the DMC catalyst complex and the MG3-15LAcompound, and polymerizing the alkylene oxide in the presence of thiscatalyst mixture. The catalyst mixture preferably also contains at leastone compound having one or more hydroxyl groups. The compound having oneor more hydroxyl groups is preferably (1) an initiator compound asdescribed before, or mixture of initiator compounds, (2) a polyethermonol or polyether polyol corresponding to the product of thepolymerization, (3) a polyether of intermediate molecular weight betweenthat of the initiator and product, (4) a mixture of two or more thereof.In cases where the catalyst mixture does not contain an initiator, it isnecessary to add an initiator compound to the reaction mixture, inaddition to the compound having one or more hydroxyl groups. Thecompound having one or more hydroxyl groups (and any added initiatorcompound) may be neutralized with or contain a small amount (such asfrom 10 to 1000 ppm) of an acid, as described in U.S. Pat. No. 6,077,978and US Published Patent Application No. 2005-0209438.

The catalyst mixture may be heated to a temperature of from 80 to 220°C., preferably from 120 to 180° C. at atmospheric or subatmosphericpressure (the residual being nitrogen or other inert atmosphere) for aperiod of 10 minutes or more, prior to performing the polymerization.This preliminary heating step is preferably performed in the presence ofa compound having one or more hydroxyl groups. This preliminary heatingstep is preferably performed in the absence of an alkylene oxide. Thecompound having one or more hydroxyl groups in this preferred process ispreferably (1) an initiator compound as described before, or mixture ofinitiator compounds, (2) a polyether monol or polyether polyolcorresponding to the product of the polymerization, (3) a polyether ofintermediate molecular weight between that of the initiator and product,or (4) a mixture of two or more of the foregoing. Most preferably, thatcompound is an initiator compound, and/or a polyether monol or polyetherpolyol corresponding to the product of the polymerization. Thispreliminary heating step may cause an alcoholate of the magnesium, group3-group 15 metal or lanthanide series metal and the initiator compoundand/or polyether monol or polyol, as the case may be, to form in situ.This reaction is believed to generate the conjugate acid of some or allof the anion(s) originally present on the starting MG3-15LA compound.Such a conjugate acid preferably is more volatile than the initiatorcompound or polyether monol or polyether polyol and in such a case isbelieved to become volatilized under the conditions of the heating stepto form a gas which is removed from the mixture during or after thepreliminary heating step. The preliminary heating step is particularlypreferred when the MG3-15LA compound includes amide anions.

The alkylene oxide polymerization is performed by polymerizing thealkylene oxide in the presence of the catalyst mixture at an elevatedtemperature. The reaction temperature is typically at least 80° C.,preferably at least 120° C., and more preferably at least 140° C. Thereaction temperature may be 200° C. or higher, but it is preferred thatthe temperature does not exceed 190° C., more preferably 180° C., inorder to maintain workable reactor pressures, to avoid forming asignificant amount of volatile impurities or other by-products, and tomaintain adequate catalyst activity without deactivating or decomposingthe DMC catalyst. The polymerization reaction usually is performed atsuperatmospheric pressures, but can be performed at atmospheric pressureor even subatmospheric pressures.

The catalyst mixture can be prepared by combining the double metalcyanide catalyst complex, the MG3-15LA compound and, preferably, acompound containing at least one hydroxyl group in the reaction vesselwhere the alkylene oxide is to be combined, or in some other vessel.

Enough of the catalyst mixture is used to provide a reasonablepolymerization rate, but it is generally desirable to use as little ofthe double metal cyanide catalyst as possible consistent with reasonablepolymerization rates, as this both reduces the cost for the catalystand, if the catalyst levels are low enough, can eliminate the need toremove catalyst residues from the product. The amount of DMC catalystcomplex may be from 1 to 5000 ppm based on the weight of the polyetherproduct. The amount of DMC catalyst complex may be at least 2 ppm, atleast 5 ppm, at least 10 ppm, at least 25 ppm, or up to 200 ppm or up to100 ppm, based on the weight of the polyether product.

The polymerization reaction can be performed batch-wise,semi-continuously (including with continuous addition of starter asdescribed in U.S. Pat. No. 5,777,177) or continuously.

In a batch polymerization, the DMC catalyst complex, the MG3-15LAcompound, alkylene oxide and initiator are charged to a reaction vesseland heated to the polymerization temperature until the desired molecularweight is obtained. One way of performing a batch polymerization is tocombine the DMC catalyst complex, MG3-15LA compound and initiator,optionally in the presence of a polyether having a hydroxyl equivalentweight up to that of the product of the polymerization, and optionallyperforming a preliminary heating step as described before. The alkyleneoxide is then added and the resulting mixture is subjected topolymerization conditions until the alkylene oxide is consumed.

In a semi-batch process, the DMC catalyst complex, MG3-15LA compound andinitiator are combined. This mixture preferably undergoes a preliminaryheating step as described before. A polyether monol or polyether polyolcorresponding to the product of the polymerization, and/or a polyetherof intermediate molecular weight between that of the initiator andproduct, may be present if desired. A portion of the alkylene oxide isintroduced into the reaction vessel and the contents of the vessel areheated if necessary to the polymerization temperature. When the DMCcatalyst complex has become activated (typically as indicated by a dropof internal reactor pressure), more alkylene oxide is fed to the reactorunder polymerization conditions. The alkylene oxide feed is continueduntil enough has been consumed to reach the target product molecularweight. Additional DMC catalyst and/or MG3-15LA compound may be addedduring the course of the alkylene oxide addition. In a semi-batchprocess, the entire amount of initiator is commonly added at the startof the process. After the alkylene oxide feed is completed, the reactionmixture may be cooked down at the polymerization temperature to consumeany remaining alkylene oxide.

A batch or semi-batch process is particularly suitable for producing apolyether having a hydroxyl equivalent weight of up to about 400, morepreferably up to about 350 or up to about 250, from an initiatorcompound having a hydroxyl equivalent weight of from 30 to 100, such asdiethylene glycol, triethylene glycol, dipropylene glycol, tripropyleneglycol, glycerin, trimethylolpropane, pentaerythritol, sucrose orsorbitol, or alkoxylates of any thereof having a hydroxyl equivalentweight of up to 100. However, batch and semi-batch processes also can beused to make polyethers having higher equivalent weights.

A continuous polymerization includes the continuous addition of at leastalkylene oxide and starter, and continuous removal of product. Acontinuous process is generally conducted by establishing steady-stateconcentrations, within the operational capabilities of thepolymerization equipment, of the DMC catalyst, the MG3-15LA compound,initiator, alkylene oxide and polymerizate under polymerizationconditions in a continuous reactor such as a loop reactor or acontinuous stirred tank reactor. The “polymerizate” is a mixture ofpolyethers that have molecular weights greater than that of theinitiator and up to that of the intended product. Additional DMCcatalyst complex, MG3-15LA compound, initiator and alkylene oxide arethen continuously added to the reactor. These can be added as a singlestream, as separate components, or in various sub-combinations.Additional catalyst mixture can be formed by combining the DMC catalystcomplex with the MG3-15LA compound, optionally with the initiatorcompound, and added during the polymerization. A product stream iscontinuously withdrawn from the reactor. The rates of the additionalstream(s) and product streams are selected to maintain steady-stateconditions in the reactor (within the capabilities of the equipment),and to produce a product having a desired molecular weight.

The product stream withdrawn from the continuous reactor may be cookeddown for some period of time to allow the unreacted alkylene oxide inthat stream to be consumed to low levels.

At the start-up of a continuous process, a mixture formed by combiningthe DMC catalyst, the MG3-15LA compound and optionally the initiatorand/or a polyether may be subjected to a preliminary heating step asdescribed before, before being contacted with the alkylene oxide. DMCcatalyst, MG3-15LA compound and initiator that are added duringsteady-state conditions may also be subjected to such a preliminaryheating step prior to introducing them into the reactor.

A continuous process is particularly suitable for producing a polyetherproduct having a hydroxyl equivalent weight from 150 to 5000, especiallyfrom 350 to 2500 and still more preferably from 500 to 2000.

In a semi-batch or continuous process as described above, the alkyleneoxide may be fed to the reactor on demand by continuously pressurizingthe reactor with the alkylene oxide to a predetermined internal reactorpressure. The concentration of unreacted alkylene oxide in a semi-batchor continuous reactor preferably is maintained at a level of from 0.01%to 10%, more preferably from 0.1% to 5% by weight, most preferably from1 to 3% by weight, during the alkylene oxide feed.

The polymerization reaction can be performed in any type of vessel thatis suitable for the pressures and temperatures encountered. In acontinuous or semi-continuous process, the vessel should have one ormore inlets through which the alkylene oxide and additional initiatorcompound can be introduced during the reaction. In a continuous process,the reactor vessel should contain at least one outlet through which aportion of the partially polymerized reaction mixture can be withdrawn.A tubular reactor that has multiple points for injecting the startingmaterials, a loop reactor, and a continuous stirred tank reactor (CTSR)are all suitable types of vessels for continuous or semi-continuousoperations. The reactor should be equipped with a means of providing orremoving heat, so the temperature of the reaction mixture can bemaintained within the required range. Suitable means include varioustypes of jacketing for thermal fluids, various types of internal orexternal heaters, and the like. A cook-down step performed oncontinuously withdrawn product is conveniently conducted in a reactorthat prevents significant back-mixing from occurring. Plug flowoperation in a pipe or tubular reactor is a preferred manner ofperforming such a cook-down step.

The product obtained in any of the foregoing processes may contain up to0.5% by weight, based on the total weight, of unreacted alkylene oxide;small quantities of the initiator compound and low molecular weightalkoxylates thereof; and small quantities of other organic impuritiesand water. Volatile impurities should be flashed or stripped from thepolyether. The product typically contains catalyst residues and residuesof the MG-15LA compound. It is typical to leave these residues in theproduct, but these can be removed if desired. Moisture and volatiles canbe removed by stripping the polyol.

The process of the invention is useful for preparing polyether polyolproducts that can have hydroxyl equivalent weights from as low as about85 to as high as about 5,000 or more.

When the hydroxyl equivalent weight of the polyether polyol product issomewhat low, such as less than about 400, the concentration of hydroxylgroups during the polymerization reaction tends to be high. For example,the concentration of hydroxyl groups is about 4.25% by weight when theproduct has an equivalent weight of 400, and this concentrationincreases to 20% when the product equivalent weight is only 85.Similarly high concentrations of hydroxyl groups are often seen duringthe early stages of a batch or semi-batch polymerization that produceshigher equivalent weight products. An advantage of this invention isthat the DMC catalyst is seen to perform well, giving excellentpolymerization rates, even when the concentration of hydroxyl groups inthe reaction mixture is high, such as in the range of from 4.25 to 20%by weight. As a result, this invention is very amenable to theproduction of polyether polyol products that have hydroxyl equivalentweights of from 85 to 500, as well as to batch and semi-batch processesin which the concentration of hydroxyl groups is from 4.25 to 20% byweight in the early stages of reaction.

The polymerization reaction can be characterized by the “build ratio”,which is defined as the ratio of the number average molecular weight ofthe polyether product to that of the initiator compound. This buildratio may be as high as 160, but is more commonly in the range of from2.5 to about 65 and still more commonly in the range of from 2.5 toabout 50. The build ratio is typically in the range of from about 2.5 toabout 15, or from about 7 to about 11 when the polyether product has ahydroxyl equivalent weight of from 85 to 400. When glycerin is theinitiator, a preferred build ratio is from 2.5 to 11.5, especially from4 to 11.5.

Certain initiators may provide specific advantages. Triethylene glycol,for example, has been found to be an especially good initiator for usein batch and semi-batch processes for producing polyether diols.Tripropylene glycol has been found to be an especially good initiatorfor use in making a catalyst mixture by combining initiator, DMCcatalyst and the MG3-15LA compound.

Polyether polyols produced in accordance with the invention are usefulfor making polyurethanes, among other things. Higher equivalent weight(500-3000 g/equivalent) polyether polyol products are useful in makingelastomeric or semi-elastomeric polyurethane, including noncellular ormicrocellular elastomers, and flexible polyurethane foams. The flexiblepolyurethane foams may be made in a slabstock or molding process.Polyether polyol products having equivalent weights of about 225 to 400are useful in making semi-flexible foams as well as the so-calledviscoelastic or “memory” foams. Polyether polyols having equivalentweights of from 85 to 400 are useful in making rigid polyurethane foams,such as thermal insulating foams for appliances, buildings, ship hullsand the like, as well as in various coating, adhesive, sealant andelastomer products. The polyether polyols tend to have properties quitesimilar to those made in conventional DMC-catalyzed polymerizationprocess and in alkali metal hydroxide-catalyzed polymerizationprocesses.

Polyether monols produced in accordance with the invention are useful assurfactants or as industrial solvents, among other uses.

The following examples are provided to illustrate the invention but arenot intended to limit the scope thereof. All parts and percentages areby weight unless otherwise indicated.

EXAMPLE 1 AND COMPARATIVE RUN A

Comparative Run A: Into the shell of a 500 ml Autoclave Engineersreactor are placed 90 g of a 255 molecular weight polypropylene oxide)triol (Voranol® CP260, The Dow Chemical Company), 3.5 microliters of a0.15 M phosphoric acid solution in water, and 0.0249 g of a zinchexacyanocobaltate catalyst complex marketed by Bayer Material Science,Inc. as Arcol 3 catalyst. The shell of the reactor is then placed on thereactor frame, and the reaction mixture is stirred and heated at atemperature of 145° C. for 90 minutes with a slow purge of nitrogen (0.5standard cubic feet per hour) passing through the reactor contents. Thereactor contents are heated to 149° C.±1.5° C., and, while maintainingthat temperature, enough propylene oxide (PO) is introduced into thereactor to produce an internal reactor pressure of 20.5±0.5 psig(141±3.49 kPa), at which time the reactor is sealed. The pressure insidethe reactor is monitored. The amount of time required for the internalreaction pressure to decline to about 10.25 psig (70.5 kPa) (1 hour and4 minutes) is recorded as the time to catalyst activation. Stillmaintaining a temperature of 149° C.+/−1.5° C., a PO feed is introducedinto the reactor, at a rate sufficient to maintain an internal reactorpressure of 27+/−3 psig (186±20.7 kPa). This feed is continued until atotal of 76.6 mL (65.8) g of PO (including the initial PO charge) hasbeen fed into the reactor. The time required to complete the PO feed (12hours, 20 minutes) is measured as an indication of polymerization rate.After all the PO has been fed into the reactor, the reaction mixture iscooked down at 149° C.±1.5° C. in an attempt to complete thepolymerization; however, a steady internal reactor pressure (indicativeof complete polymerization of the charged PO) is not achieved after 4½hours. The failure to reach a steady internal reactor pressure indicatesthat the catalyst has become substantially deactivated.

Example 1 is performed in the same manner, except this time 0.189 g ofaluminum isopropoxide (0.037 moles/g of DMC catalyst complex) is addedto the reactor after the DMC catalyst is added and thoroughly mixed intothe reaction mixture before it is heated. In this case, the activationtime is 89 minutes, but the PO feed requires only 2½ hours and a steadyinternal reaction pressure is achieved after cooking the reactionmixture down for only 28 minutes. The product has a number averagemolecular weight of about 450.

The addition of the aluminum isopropoxide is seen to very substantiallyincrease the rate of PO polymerization.

EXAMPLES 2 AND 3

Example 2: Into the shell of a 500 ml Autoclave Engineers reactor areplaced 90 g of a propoxylate of glycerin that has an average molecularweight of 260 (Voranol® CP230-660, The Dow Chemical Company). Thispolyol is a mixture of propoxylates having molecular weights from 150 to614, and contains 2% by weight glycerin. 3.6 microliters of a 0.15 Mphosphoric acid solution in water and 100 parts per million, based onthe expected mass of the product, of the Arcol 3 catalyst are added.0.0075 mole of aluminum isopropoxide/gram of DMC catalyst complex(enough to provide 20 parts per million aluminum based on the expectedmass of the product) is added and stirred in. The shell of the reactoris then placed on the reactor frame, and the reaction mixture is stirredand heated at a temperature of 145° C. for 90 minutes with a slow purgeof nitrogen (0.5 standard cubic feet per hour) passing through thereactor contents. The reactor contents are heated to 140° C., and, whilemaintaining that temperature, enough PO is introduced into the reactorto produce an internal reactor pressure of 20.5+/−0.5 psig (141±3.49kPa), at which time the reactor is sealed. The pressure inside thereactor is monitored. The amount of time (153 minutes) required forinternal reaction pressure to decline to about 10.25 psig (70.5 kPa) isrecorded as the time to catalyst activation. Still maintaining atemperature of 140° C., a PO feed is introduced into the reactor, at arate sufficient to maintain an internal reactor pressure of 27±3 psig(186±20.7 kPa). This feed is continued until a total of 76.6 mL (65.8) gof PO (including the initial PO charge) has been fed into the reactor.The time required to complete the PO feed after the catalyst has becomeactivated is 5 hrs and 17 minutes. After all the PO has been fed intothe reactor, the reaction mixture is cooked down at 140° C. for 88minutes, until a steady internal reactor pressure (indicative ofcomplete polymerization of the charged PO) is achieved. A 450 numberaverage molecular weight product is obtained having a polydispersity of1.1.

Example 3 is performed in the same manner, except that the amount of thealuminum isopropoxide is increased to 0.1875 moles per gram of DMCcatalyst complex (500 ppm of aluminum based on the expected mass of theproduct). A 450 number average molecular weight product having apolydispersity of 1.08 is obtained. The activation time in this case is61 minutes; the time to feed the PO after the catalyst complex hasbecome activated is 3 hours and 16 minutes, and the cook down time is 29minutes. The higher amount of aluminum isopropoxide in Example 3 is seento provide for both a faster activation of the catalyst as well as afaster polymerization rate after the catalyst has become activated.

EXAMPLES 4 AND 5

Example 4 is performed in the same manner as Example 2, except thepolymerization temperature is 160° C. The activation time is 68 minutes,the additional time to feed PO is 3 hours and 24 minutes, and the cookdown time at the end of the batch is 20 minutes.

Example 5 is performed in the same manner as Example 3, except thepolymerization temperature is 160° C. The activation time is 22 minutes,the additional time to feed PO is less than 4 hours, and the cook downtime at the end of the batch is 21 minutes.

EXAMPLES 6 AND 7

Example 6 is performed in the same manner as Example 2, except thepolymerization temperature is 160° C., the amount of DMC catalystcomplex is 220 parts per million, based on the expected mass of theproduct, and the amount of aluminum isopropoxide is enough to provide 44parts per million aluminum based on the expected mass of the product(0.0165 mole of aluminum isopropoxide/gram of DMC catalyst complex). Theactivation time is 21 minutes, the time needed to feed the PO after thecatalyst has become activated is 2 hours and 30 minutes, and the cookdown time at the end of the batch is 21 minutes.

Example 7 is performed in the same manner as Example 6, except theamount of aluminum isopropoxide is enough to provide 1100 parts permillion aluminum based on the expected mass of the product (0.4125 moleof aluminum isopropoxide/gram of DMC catalyst complex). The activationtime is 28 minutes, the time needed to feed the PO after the catalysthas become activated is 2 hours and 5 minutes, and the cook down time atthe end of the batch is 30 minutes.

EXAMPLE 8 AND COMPARATIVE RUN B

Into the shell of a 500 mL Autoclave Engineers reactor are placed 5 g ofsorbitol and 95 g of a propoxylated sorbitol that has an averageequivalent weight of 117 (Voranol® RN 482, The Dow Chemical Company).5.3 microliters of a 0.15 M phosphoric acid solution in water. The shellof the reactor is then placed on the reactor frame, and the reactorcontents are heated to 60° C. for one hour with stirring and with a slowpurge of nitrogen (0.5 standard cubic feet per hour). The reactorcontents are cooled to 40° C. and 0.0286 g of the Arcol 3 catalyst areadded, followed by 0.108 g of aluminum isopropoxide (0.0185 moles per gof DMC catalyst complex). The reaction mixture is heated to 60° C. withstirring and a nitrogen purge and then allowed to cool to 20° C., atwhich temperature stirring under nitrogen is continued overnight. Thereaction mixture is then stirred and heated at a temperature of 145° C.for 90 minutes with a slow purge of nitrogen (0.5 standard cubic feetper hour) passing through the reactor contents. The nitrogen purge isdiscontinued, the reactor contents are heated to 150° C., and, whilemaintaining that temperature, 11.1 mL of PO is introduced at the rate of1 mL/minute to produce an internal reactor pressure of 29.5 psig (203kPa), at which time the reactor is sealed. The mixture is stirred for 90seconds and then the PO addition is resumed at the rate of 0.05mL/minute. Five minutes after the PO addition is resumed, the pressureinside the reactor drops to 28.7 psig (198 kPa) (indicating that thecatalyst has become activated) and at that time the PO addition rate isincreased again to 0.10 mL/minute. The pressure inside the reactor ismonitored. Once the pressure reaches 34 psig (234 kPa), the PO additionrate is again decreased to 0.07 mL/minute, until a total of 16.7 mL ofPO has been added. The PO feed is then stopped, and the reactor contentsstirred at 150° C. until the reactor declines to 1.95 psig (13.4 kPa) (4hours and 20 minutes). A 450 number average molecular weight product isobtained.

Comparative Run B is performed in the same general manner, except thatno aluminum isopropoxide is added and the PO is fed slightlydifferently. In Comparative Run B, 12 mL of PO is added at the rate of1.0 mL/minute to charge the reactor to 29 psig (203 kPa). 2.5 hours at150° C. are needed to activate the catalyst (as indicated by a drop ininternal reactor pressure to 28.7 psig (198 kPa)), and then 2.2 mL PO isfed at 0.1 mL/minute. After all the PO is added, the reactor is cookeddown for 6½ hours, at which time the reactor pressure has only declinedto 24.2 psig (167 kPa), indicating a very slow polymerization, comparedwith Example 8.

EXAMPLE 9 AND COMPARATIVE RUN C

Example 9: Into the shell of a 10-liter stainless steel alkoxylationreactor are placed 3143 g of the Voranol® CP-260 polyol described beforeand 0.36 grams of an 85% by weight phosphoric acid solution in water.The shell of the reactor is then placed on the reactor frame and thereactor contents are heated to 150° C. for thirty minutes under vacuum.1.099 g of the Arcol 3 catalyst is separately mixed into 390 g of thesame Voranol CP-260 polyol and added to the reactor, which is then keptunder vacuum at 150° C. for one hour. 8.4 g of aluminum isopropoxide(0.037 moles/g DMC catalyst complex) are mixed into another 523 g of thepolyol and added to the reactor. The reactor contents are then heated at150° C. under vacuum for about 45 minutes. 452 g of PO are fed to thereactor at the rate of 60 g/minute while maintaining the temperature at150° C. When the reactor pressure declines to 0.3 bar (30 kPa), 2550 gof PO are fed in over 59 minutes. The reactor contents are then digestedat 150° C. for 2 hours, and the product is then cooled down anddigested. The hydroxyl number of the resulting product is 372 mg KOH/g(452 molecular weight); its viscosity is 368 cSt at 25° C.

Comparative Run C is performed in the same general manner. The initialcharge to the reactor consists of 3066 g of the Voranol® CP-260 polyoldescribed before and 0.31 grams of an 85% by weight phosphoric acidsolution in water. The shell of the reactor is then placed on thereactor frame, and the reactor contents are heated to 130° C. for threehours under vacuum. 0.966 g of the Arcol 3 catalyst is separately mixedinto 476 g of the same Voranol CP-260 polyol and added to the reactor,which is then kept under vacuum at 150° C. for thirty minutes. 394 g ofPO are fed to the reactor at the rate of 60 g/minute while maintainingthe temperature at 150° C. When the reactor pressure declines to 0.3 bar30 kPa), 2220 g of PO are fed in over 139 minutes. The lower PO additionrate reflects the much slower polymerization rate in this run, comparedto Example 9. The reactor contents are then digested at 150° C. for 2hours, and the product is then cooled down and collected.

The hydroxyl number of the resulting product is 380 mg KOH/g (443molecular weight); its viscosity is 360 cSt at 25° C. The products ofExample 9 and Comparative Run C therefore are essentially identical.

EXAMPLE 10 AND COMPARATIVE RUN D

Example 10: 60 grams of a 450 molecular weight poly(propylene oxide)triol acidified with 300 ppm of an 85% phosphoric acid solution inwater, 0.030 g of the Arcol 3 catalyst and 37.5 microliters of a 1 Msolution of diethyl zinc in hexane are mixed with stirring for 10minutes at 130° C. Fifty grams of this mixture are transferred to a 300mL pressure reactor, where it is heated to 160° C. with stirring andsparged with nitrogen for two hours. PO is then pumped into the reactorat the rate of 0.25 mL/minute. After about 2 mL have been added,glycerin that has been acidified with 70 ppm phosphoric acid is fed intothe reactor at the rate of 0.44 mL/minute. The pressure in the reactoris monitored during the PO and glycerin feeds. The pressure remainsbelow 20 psig (138 kPa) for well over 150 minutes, is still below 40psig (276 kPa) after 200 minutes, and reaches 53 psig (365 kPa) after245 minutes of the feeds. At this time the feeds are discontinued andthe reactor contents are digested at 160° C. for one hour. 110 g ofpolyol are obtained. The DMC catalyst loading in the product is 227 ppm.

Comparative Run D is performed in the same manner, except the diethylzinc solution is omitted. In this case, the pressure in the reactorincreases much more rapidly than is seen in Example 10, reaching 44 psig(303 kPa) after only 109 minutes. The faster increase in reactorpressure indicates a significantly slower polymerization rate than isseen in Example 10. The feeds are discontinued at this point, and 73 gof a polyol that contains 342 ppm of the DMC catalyst are obtained.Comparative Run D polymerizes more slowly, produces less product perunit time, and requires a higher catalyst level than Example 10.

EXAMPLE 11 AND COMPARATIVE RUN E

Example 11: 60 grams of a 700 molecular weight poly(propylene oxide)triol (Voranol® 270, The Dow Chemical Company) and 0.015 g of the Arcol3 catalyst are stirred together. 4.3 mg of an 85% phosphoric acidsolution in water are added and the mixture is stirred again. Then, 0.61mL of a 1.6 M solution of diethylaluminum ethoxide in toluene is added,followed by stirring for 10 minutes at 130° C. Fifty grams of thismixture are transferred to a 300 mL pressure reactor, where it is heatedto 150° C. with stirring and sparged with nitrogen for two hours. PO isthen pumped into the reactor at the rate of 1.0 mL/minute. After about28 mL of PO have been added, glycerin that has been acidified with 70ppm phosphoric acid is fed into the reactor at the rate of 0.061mL/minute while continuing the PO feed. Propylene oxide pressures in thereactor remain well below 20 psig (138 kPa) during this addition. Afterabout 100 minutes of the PO and glycerin feeds, the feeds arediscontinued for about 5 minutes, and then resumed at the same feedrates for approximately 10 more minutes. The reactor contents are thenallowed to digest at 150° C. Internal reactor pressure rapidly decreasesto about zero, indicating that the catalyst remains active and theremaining PO polymerizes quickly. After digesting for about 60 minutes,the PO and glycerin feeds are again resumed at half their previousrates, for about one hour. Again propylene oxide pressures remain below20 psig (138 kPa) as the PO and glycerin are fed to the reactor. Theproduct has a molecular weight of about 1100.

When Example 11 is repeated without the diethylaluminum ethoxide(Comparative Run E), propylene oxide pressure inside the reactor buildsto 30 psig (207 kPa) after about 55 minutes of the PO and glycerinfeeds. This pressure build-up indicates that the catalyst is performingsluggishly and cannot polymerize the PO at the rate at which it is beingfed in. After digesting the reactor contents for about 40 minutes, thePO and glycerin feeds are resumed at one-half the initial rates, and theinternal reactor pressure is again seen to rise as the reactants arefed.

EXAMPLES 12 AND 13 AND COMPARATIVE RUN F

Example 12: 50 grams of a 700 molecular weight poly(propylene oxide)triol (Voranol® 270, The Dow Chemical Company) that is acidified with100 ppm phosphoric acid and 0.0125 g of the Arcol 3 catalyst are stirredtogether in a 300 mL pressure reactor. Then, 37.5 mg of aluminumisopropoxide (about 0.147 moles/gram DMC catalyst complex) are added,and the resulting mixture is heated to 150° C. with stirring and spargedwith nitrogen for two hours. PO is then pumped into the reactor at therate of 0.5 mL/minute. After about 28 mL of PO have been added, glycerinthat has been acidified with 70 ppm phosphoric acid is fed into thereactor at the rate of 0.03 mL/minute. These feeds are continued forabout 200 minutes, until a total of 130 mL of PO has been fed into thereactor. Pressures in the reactor remain well below 10 psig (69 kPa)during this entire addition. After a short digestion at 150° C., an 1100molecular weight polyol is obtained.

Example 13 is performed in the same manner, except that the amount ofaluminum isopropoxide is increased to 111 mg (about 0.44 molesaluminum/g DMC catalyst complex), and after digesting at 150° C.,additional PO is fed at the rate of 0.5 mL/minute for about 60 minutes.Internal reactor pressures remain under 20 psig (138 kPa) during theentire polymerization, once the catalyst has become activated. An 1100molecular weight polyol is obtained.

Comparative Run F is run in the same manner, except no aluminumisopropoxide is provided, the propylene oxide feed rate is only 0.35mL/minutes and the glycerin feed rate is only 0.02 mL/minute. Catalystactivation is slower than in Examples 12 and 13, and reactor pressureincreases to 30 psig (207 kPa) after about 70 minutes of the PO/glycerinfeeds. The feeds are discontinued when the pressure reaches 30 psig (207kPa), and the reactor contents are digested until the reactor pressurefalls to approximately zero. The PO and glycerin feeds are thenre-started, and again the internal reactor pressure increases rapidly to30 psig (207 kPa).

EXAMPLE 14

Into the shell of a 500 mL Autoclave Engineers reactor are placed 74.3 gof a 450 molecular weight polypropylene oxide triol) (Voranol® CP-450,The Dow Chemical Company). 2.85 microliters of a 0.15% by weightphosphoric acid solution in water and 0.035 of the Arcol 3 catalyst.After stirring, 0.265 g (about 0.37 moles/gram of DMC catalyst complex)aluminum isopropoxide are added, and the mixture is stirred again. Theshell of the reactor is then placed on the reactor frame, and thereactor contents are heated to 140° C. for 90 minutes with stirring andwith a slow purge of nitrogen (0.5 standard cubic feet per hour). Thereaction mixture is heated to 159° C. with stirring and, whilemaintaining that temperature, 50.8 mL of PO is introduced at the rate of1 mL/minute. The catalyst activates before the internal reactor pressurereaches 10 psig (69 kPa). Once the catalyst has become activated (asevidenced by a drop in the internal reactor pressure), the PO feed rateis decreased to 0.5 mL/minute and a glycerin feed (0.063 g/minute) isbegun. The PO and glycerin feeds are continued for 2.5 hours, duringwhich time the internal reactor pressure increases only to 9 psig (62kPa). The PO feed rate is increased to 1.03 mL/minute and the glycerinfeed rate is increased to 0.127 g/minute for 90 minutes, during whichtime the internal reactor pressure increases to only 15 psig (103 kPa).At this point the PO and glycerin feed rates are again increased, to1.29 mL/minute and 0.158 g/minute, respectively, resulting in a slowincrease in internal reactor pressure to 23.5 psig (162 kPa). Thereaction contents are digested at 159° C. for 30 minutes. The total POfeed is 252.7 mL and the total amount of glycerin fed is 31.3 g. Totalco-feed time is 5 hours. 340 g of polyol are obtained (97% yield). Thepolyol molecular weight is 700, with a polydispersity of 1.13.

EXAMPLE 15

Into the shell of a 500 ml Autoclave Engineers reactor are placed 66.7 gof a 255 molecular weight polypropylene oxide triol) (Voranol® CP-260,The Dow Chemical Company), 3.0 microliters of a 0.15% by weightphosphoric acid solution in water and 0.035 of a zinc hexacyanocobaltatecatalyst complex. After stirring, 0.265 g (about 0.37 moles/gram of DMCcatalyst complex) aluminum isopropoxide are added, and the mixture isstirred again. The shell of the reactor is then placed on the reactorframe, and the reactor contents are heated to 145° C. for 90 minuteswith stirring and with a slow purge of nitrogen (0.5 standard cubic feetper hour). The reaction mixture is heated to 164° C. with stirring and,while maintaining that temperature, PO is introduced at the rate of 1mL/minute until the internal reactor pressure reaches 20.3 psig (140kPa), at which time the PO feed rate is decreased to 0.5 mL/minute. Whenthe internal reactor pressure declines to 18 psig (124 kPa), the PO feedrate is increased to 0.75 mL/minute, and the reactor pressure continuesto decline. After a total of 60.1 mL of PO has been added, the PO feedrate is decreased to 0.25 mL/minute and a glycerin feed (0.05 g/minute)is begun. The internal reactor pressure at the point the glycerin feedis begun is only 2.8 psig (19 kPa). The PO and glycerin feeds arecontinued until the internal reactor pressure increases to 44.5 psig(307 kPa), at which point the reactor contents are digested at 164° C.for 55 minutes. The total feed time is 7 hours and 10 minutes. Theproduct polyol has a molecular weight of 449, a polydispersity of 1.09,and contains 152 ppm of the DMC catalyst complex.

EXAMPLE 16 AND COMPARATIVE RUN G

Example 16: Into the shell of a 500 ml Autoclave Engineers reactor areplaced 90 g of a 255 molecular weight polypropylene oxide triol)(Voranol® CP-260, The Dow Chemical Company), 3.5 microliters of a 0.15%by weight phosphoric acid solution in water and 0.0249 of the Arcol 3catalyst. After stirring, 0.085 g (about 0.011 moles/gram of DMCcatalyst complex) of stannous ethyl hexanoate are added, and the mixtureis stirred again. The shell of the reactor is then placed on the reactorframe, and the reactor contents are heated to 145° C. for 90 minuteswith stirring and with a slow purge of nitrogen (0.5 standard cubic feet(14 liters) per hour). The reaction mixture is heated to 149° C. withstirring and, while maintaining that temperature, PO is introduced untilthe internal reactor pressure reaches 20.5 psig (141 kPa), at which timethe PO feed rate is stopped and the reactor contents digested at 149° C.The reactor pressure decreases to about 10 psig (69 kPa) after 3 hoursand 53 minutes. PO is then fed into the reactor for 3 hours and 19minutes, at a rate which maintains a reactor pressure of 27±3 psig(186±20.7 kPa). The reactor contents are then digested for 40 minutesuntil a constant PO pressure of near zero is obtained. The total amountof PO charged to the reactor is 79.7 mL.

Comparative Run G is performed in the same manner, except the stannousethyl hexanoate is omitted. The catalyst activates in 50 minutes, butthe PO feed requires 11 hours and 40 minutes. After a total of 79.7 mLof PO is introduced to the reactor, the reactor contents are digestedfor 4.5 hours to achieve a constant internal reactor pressure. The slowfeed rates and long digestion time indicate that the catalyst is muchmore sluggish that in Example 16.

EXAMPLE 17

Into the shell of a 500 ml Autoclave Engineers reactor are placed 90 gof a 255 molecular weight polypropylene oxide triol) (Voranol® CP-260,The Dow Chemical Company), 3.5 microliters of a 0.15% by weightphosphoric acid solution in water and 0.0249 of the Arcol 3 catalyst.After stirring, 0.038 g (about 0.008 moles/gram of DMC catalyst complex)of stannous methoxide is added, and the mixture is stirred again. Theshell of the reactor is then placed on the reactor frame, and thereactor contents are heated to 145° C. for 90 minutes with stirring andwith a slow purge of nitrogen (0.5 standard cubic feet (14 liters) perhour). The reaction mixture is heated to 149° C. with stirring and,while maintaining that temperature, PO is introduced until the internalreactor pressure reaches 20.5 psig (141 kPa), at which time the PO feedrate is stopped and the reactor contents digested at 149° C. The reactorpressure decreases to about 10 psig (69 kPa) after 1 hour and 39minutes. PO is then fed into the reactor for 3 hours, at a rate whichmaintains a reactor pressure of 27±3 psig (186±20.7 kPa). The reactorcontents are then digested for 20 minutes until a constant PO pressureof near zero is obtained. The total amount of PO charged to the reactoris 79.7 mL. The resulting polyol has a molecular weight of 436 and apolydispersity of 1.1.

EXAMPLE 18

150 grams of a 260 molecular weight poly(propylene oxide) triol(Voranol® CP-260) is acidified with 300 ppm of an 85% phosphoric acidsolution in water, and mixed with 0.052 g of the Arcol 3 catalyst. 306microliters of a 1 M solution of diethyl zinc in hexane (about 0.006moles Zn/g DMC catalyst complex) are then mixed in, and the resultingmixture is heated under nitrogen at 130° C. for 15 minutes. 57.8 gramsof this mixture are transferred to the shell of a 500 mL pressurereactor, where it is heated to 145° C. with stirring and sparged withnitrogen for 90 minutes. The reaction mixture is heated to 164° C. withstirring and, while maintaining that temperature, PO is fed into thereactor at the rate of 1.0 mL/minute. The catalyst activatesimmediately, and the reactor pressure remains at or below 7.2 psig (50kPa). The PO feed rate is decreased to 0.27 mL/minute and a glycerinco-feed is introduced at the rate of 0.056 g/minute. The PO and glycerinfeeds are continued for 3 hours and 33 minutes, until the internalreactor pressure reaches 50 psig (345 kPa), at which time the PO feedrate is stopped and the reactor contents digested at 164° C. The totalamount of PO charged to the reactor is 51.1 mL. The resulting polyol hasa molecular weight of about 450 and contains about 132 ppm of the DMCcatalyst complex.

EXAMPLE 19

Into the shell of a 500 ml Autoclave Engineers reactor are placed 50 gof a 400 molecular weight poly(propylene oxide) diol (Voranol® P-400,The Dow Chemical Company), 5.0 grams of propylene glycol, 0.23microliters of a 0.15% by weight phosphoric acid solution in water, 0.02g of the Arcol 3 catalyst and 0.151 g (about 0.037 moles/gram of DMCcatalyst complex) of aluminum isopropoxide. The shell of the reactor isthen placed on the reactor frame, and the reactor contents are heated to145° C. for 90 minutes with stirring and with a slow purge of nitrogen(0.5 standard cubic feet (14 liters) per hour). The reaction mixture isheated to 150° C. with stirring and, while maintaining that temperature,32.4 mL of PO is introduced at the rate of 1 mL/minute. The PO begins toreact immediately, and the internal reactor pressure reaches only 15psig (103 kPa) during the initial PO feed. The reactor temperature isthen increased to 160° C., and PO and propylene glycol are co-fed to thereactor at a weight ratio of 4.26 g PO per gram of propylene glycol,until a total of 118.4 mL PO and 22.6 g of propylene glycol have beenadded. The addition rates are varied to maintain a reactor pressure of25±4 psig (172±27.6 kPa) in the reactor during the co-feed. It takes 10hours to complete the co-feed, and an additional hour of digestion at160° C. to obtain a constant internal reaction pressure. The product hasa molecular weight of about 400 and contains about 100 ppm of the DMCcatalyst complex.

EXAMPLES 20-21 AND COMPARATIVE RUN H

Example 20: Into the shell of a 500 ml Autoclave Engineers reactor areplaced 90 g of a propoxylate of glycerin that has an average molecularweight of 260 (Voranol® CP230-660, The Dow Chemical Company). 3.5microliters of a 0.15 M phosphoric acid solution in water and 0.0249 gof the Arcol 3 catalyst are added. 0.041 mole of aluminumsec-butoxide/gram of DMC catalyst complex (enough to provide 160 partsper million aluminum based on the expected mass of the product) is addedand stirred in. The shell of the reactor is then placed on the reactorframe, and the reaction mixture is stirred and heated at a temperatureof 145° C. for 90 minutes with a slow purge of nitrogen (0.5 standardcubic feet per hour) passing through the reactor contents. The reactorcontents are heated to 150° C., and, while maintaining that temperature,enough propylene oxide (PO) is introduced into the reactor to produce aninternal reactor pressure of 20.5±0.5 psig (141±3.49 kPa), at which timethe reactor is sealed. The pressure inside the reactor is monitored. Thetime to catalyst activation is 40 minutes. Still maintaining atemperature of 150° C., a PO feed is introduced into the reactor, at arate sufficient to maintain an internal reactor pressure of 25±3 psig(172±20.7 kPa). This feed is continued until a total of 79.7 ml (65.8) gof PO (including the initial PO charge) has been fed into the reactor.The time required to complete the PO feed after catalyst activation is 3hrs and 15 minutes. After all the PO has been fed into the reactor, thereaction mixture is cooked down at 150° C. until a steady internalreactor pressure (indicative of complete polymerization of the chargedPO) is achieved. The PO digest time for this reaction is 30 minutes. A450 number average molecular weight product having a polydispersity of1.1 is obtained.

Example 21: Into the shell of a 500 ml Autoclave Engineers reactor areplaced 90 g of a propoxylate of glycerin that has an average molecularweight of 260 (Voranol® CP230-660, The Dow Chemical Company). 3.5microliters of a 0.15 M phosphoric acid solution in water, and 0.0249 gof the Arcol 3 catalyst are added. 0.0042 mole of stannouspyrophosphate/gram of DMC catalyst complex (0.0021 moles of tin/gram ofDMC catalyst complex; enough to provide 160 parts per million of tin(II) based on the expected mass of the product) is added and stirred in.The shell of the reactor is then placed on the reactor frame, and thereaction mixture is stirred and heated at a temperature of 145° C. for90 minutes with a slow purge of nitrogen (0.5 standard cubic feet (14liters) per hour) passing through the reactor contents. The reactorcontents are heated to 150° C., and, while maintaining that temperature,enough propylene oxide (PO) is introduced into the reactor to produce aninternal reactor pressure of 20.5±0.5 psig (141±3.49 kPa), at which timethe reactor is sealed. The pressure inside the reactor is monitored. Thetime to catalyst activation is 27 minutes. Still maintaining atemperature of 150° C., a PO feed is introduced into the reactor, at arate sufficient to maintain an internal reactor pressure of 25±3 psig(172±20.7 kPa). This feed is continued until a total of 79.7 mL (65.8) gof PO (including the initial PO charge) has been fed into the reactor.The time required to complete the PO feed after catalyst activation is 6hrs and 50 minutes. After all the PO has been fed into the reactor, thereaction mixture is cooked down at 150° C. until a steady internalreactor pressure (indicative of complete polymerization of the chargedPO) is achieved. The PO digest time for this reaction is 77 minutes. A403 number average molecular weight product is obtained having apolydispersity of 1.07.

Comparative run H is performed in the same manner as Example 20, exceptthis time no aluminum sec-butoxide is added to the reactor. In thiscase, the activation time is 40 minutes, but the PO feed requires 9 hrsand 17 minutes and a steady internal reaction pressure is not achievedafter cooking the reaction mixture down for more than 35 minutes. Theproduct has a number average molecular weight of about 450.

The addition of the aluminum sec-butoxide or stannous pyrophosphate isseen to very substantially increase the rate of PO polymerization.

EXAMPLES 22-29 AND COMPARATIVE RUNS I-O

Additive screening tests (Examples 22-26 and 29) are performed in a48-well Symyx Technologies Parallel Pressure Reactor equipped with asyringe pump connected to a robotically controlled needle withcompressed microvalve for injection of propylene oxide. Additives arescreened at a loading of 25.4 micromoles in each well. In each case, 36mg of the Arcol 3 catalyst, 74.16 g of a 700 molecular weightpolypropylene oxide) triol (Voranol® 270), and 10 microliters ofphosphoric acid are mixed and heated at 130° C. for 30 minutes withstirring. 2 mL of the resulting suspension is added to a reactor tubecontaining the additive, followed by 20 microliters of glycerol. Thetubes are then loaded into the reactor and heated to 150° C. 0.66 mL ofpropylene oxide is added to each well all at once. The reaction mixtureis heated for 4 hours at 150° C., cooled to room temperature, andvented. The pressure inside each well is monitored during the heating.The time at which a large pressure drop is seen is taken as the time ofcatalyst activation.

Example 27 is performed in the same general manner, except aluminumisopropoxide (4.9 mmol), zinc methoxide (7.8 mmol) and DMC (250 ppm) ina mixture of Voranol 270 acidified 100 ppm H₃PO₄ (2 mL), 20 mL glyceroland PO (0.5 mL) at 150° C. are used.

Example 28 is performed in the same general manner, except diantimonytris(ethylene glycolate) (7.75 mmol) and DMC (250 ppm) in a mixture ofVoranol 270 acidified 100 ppm H₃PO₄ (2 mL), 20 mL glycerol and PO (0.5mL) at 150° C. are used.

The Comparative Runs are performed in the same manner, either withoutthe DMC catalyst (Comparative Runs I-N) or without any additive(Comparative Run O).

The additives screened in each case, and the results obtained, are asindicated in Table 1 below.

TABLE 1 Example or Comparative DMC Run Additive Type catalyst Time toactivation 22 Diethylaluminum Present Less than 40 minutes ethoxide 23Aluminum Present Approximately 30 minutes isopropoxide 24 Hafnium tetrat- Present Approximately 30 minutes butoxide 25 Zirconium tetra t-Present Less than 40 minutes butoxide 26 Titanium tetra t- PresentApproximately 50 minutes butoxide 27 Aluminum Present Approximately 15minutes isopropoxide and zinc methoxide 28 Antimony (III) PresentApproximately 2 hours glycolate 29 Diethyl zinc Present Approximately 10minutes I Diethylaluminum None Minimal polymerization ethoxide within 4hours J Aluminum None Minimal polymerization isopropoxide within 4 hoursK Hafnium tetra t- None Minimal polymerization butoxide within 4 hours LZirconium tetra t- None Minimal polymerization butoxide within 4 hours MTitanium tetra t- None Minimal polymerization butoxide within 4 hours NDiethyl zinc None Minimal polymerization within 4 hours O None PresentNo activation within 4 hours

As can be seen from the data in Table 1, the DMC catalyst by itselffails to activate within four hours (Comparative Run O), but activatesrapidly when any of the additives are present. Comparative Runs I-Ndemonstrate that the additives by themselves are ineffective POpolymerization catalysts.

EXAMPLE 30 AND COMPARATIVE RUN P

Comparative Run P: Into a jar containing 30 g of a 700 molecular weightpoly(propylene oxide) triol (Voranol 270, from The Dow Chemical Company)acidified with 100 ppm H₃PO₄ is added 24.8 mg of zinc chloride (0.0243moles zinc/gram of DMC catalyst complex). 7.5 mg of the Arcol 3 catalystis then added and the mixture is heated at 150° C. for 1.25 hours undera nitrogen flow. 2 mL of the resulting suspension is added to a reactortube containing 20 microliters of glycerol. The tubes are then heated to150° C. 0.50 mL of propylene oxide is added to all at once. The reactionmixture is heated for 3.5 hours at 150° C., cooled to room temperature,and vented. The pressure inside the tube is monitored during theheating. Even after 200 minutes, there is barely any pressure dropwithin the tube, which indicates that the DMC catalyst has failed toactivate.

Example 30 is performed in the same manner, substituting 12.1 micromolesof diethyl zinc for the zinc chloride. In this case a large pressuredrop, indicating that the catalyst has become activated, is seen within20 to 30 minutes after the alkylene oxide is added.

EXAMPLES 31-32 AND COMPARATIVE RUN R

Example 31: 120 grams of a 700 molecular weight polypropylene oxide)triol are mixed with 30 mg of phosphoric acid, 20 mg of the Arcol 3catalyst and 0.35 g of hafnium tetra(tert-butoxide). 100 grams of themixture are placed into the shell of a 600 mL pressure reactor andheated under a nitrogen sparge for 140° C. for 90 minutes. Nitrogenpressure is relieved to zero gauge pressure. Propylene oxide is fed intothe reactor at a rate of 0.7 mL/minute of propylene oxide for 10minutes, while keeping the reactor temperature at 140° C. The reactor isthen maintained at the same temperature until a sharp drop in internalreactor pressure is seen, indicating that the catalyst has becomeactivated. More propylene oxide is then added, at the same temperatureand at a flow rate of 1.5 mL/minutes until approximately 380 mL has beenadded. The reactor contents are then digested at 140° C. until aconstant reactor pressure is obtained, and the product is then cooleddown.

The product contains 201 ppm of an ultra-high molecular weight polymer,as measured by GPC using Waters 2690/5 Separations Module and 410 RIDetector in combination with the Empower Pro Software. The column is aPL-gel column (30 cm×0.7 internal diameter) filled 5 micron PS/DVBcopolymer particles having a pore size of 1000 angstroms. The eluent istetrahydrofuran, at a flow rate of 1 mL/minute. The detector temperatureis 35° C., the peak width is greater than 0.2 min, attenuation is 62,500nRIU, 1 V output and 12 minutes run time. The GPC system was calibratedusing narrow polystyrene standards EasiCal PS-1 A/B and a polystyrene100 kDa narrow standard diluted in THF to concentrations in the rangefrom 180 to 1.8 mg PS/L. HMWT as reported here is the fraction of thedistribution whose molecular weight is higher than 40,000 g/mol.

Example 32: Example 31 is repeated, substituting an equal amounttitanium isopropoxide for the hafnium tetra(tert-butoxide). The productcontains 784 ppm of the ultra-high molecular weight tail.

Comparative Run R is performed in the same way, but no hafnium ortitanium compound is present. The catalyst activates more slowly, andperforms sluggishly at the end of the propylene oxide feed. The productcontains 1196 ppm of the ultra-high molecular weight tail.

EXAMPLE 33, 34, 35 AND COMPARATIVE RUN S

Example 33: Into the shell of a 500 mL Autoclave Engineers reactor areplaced 45 g of a propoxylate of glycerin that has an average molecularweight of 450 (Voranol® CP450, The Dow Chemical Company). 1.7microliters of a 0.15 M phosphoric acid solution in water, and 0.0030 gof the Arcol 3 catalyst. 0.037 mole of Aluminum isopropoxide/gram of DMCcatalyst complex (enough to provide 10 parts per million of aluminumbased on the expected mass of the product) is added and stirred in. Theshell of the reactor is then placed on the reactor frame, and thereaction mixture is stirred and heated at a temperature of 145° C. for90 minutes with a slow purge of nitrogen (0.5 standard cubic feet (14liters) per hour) passing through the reactor contents. The reactorcontents are heated to 150° C., and, while maintaining that temperature,propylene oxide (PO) is introduced into the reactor at a rate of 1.0mL/min. The reactor initially climbs to an internal reactor pressure of16.8 psig (116 kPa), at which time the pressure begins to decline slowlyto a pressure of 6.2 psig (43 kPa) with a constant feed of PO at 1.0mL/min. There is no pause in PO feed for catalyst activation. Eventuallythe pressure in the reactor begins to rise due to the compression ofnitrogen gas in the reactor. The feed is continued until a total of309.1 mL (255.0 g) of PO has been fed into the reactor. The timerequired to complete the PO feed is 5 hrs and 24 minutes. After all thePO has been fed into the reactor, the reaction mixture is cooked down at150° C. until a steady internal reactor pressure (indicative of completepolymerization of the charged PO) is achieved. The PO digest time forthis reaction is 12 minutes. A 3000 number average molecular weightproduct is obtained. The final DMC catalyst concentration in the reactoris 10 ppm.

Example 34 is performed in the same general manner as Example 33, exceptthe amount of the DMC catalyst complex is reduced by 50% (to a finalconcentration of 5 ppm. The time to catalyst activation is 12 minutes.The time required to complete the PO feed is 3 hrs and 55 minutes. ThePO digest time for this reaction is 18 minutes. A 3000 number averagemolecular weight product is obtained.

Example 35 is performed in the same general manner as Example 33, exceptthe amount of the DMC catalyst complex is reduced to 2.5 ppm, based onthe weight of the final product, and the amount of aluminum isopropoxideis only 0.0008 g (0.037 mole of aluminum per gram of DMC catalystcomplex. The time to catalyst activation is 32 minutes. The timerequired to complete the PO feed is 6 hrs and 12 minutes. The PO digesttime for this reaction is 49 minutes. A 3000 number average molecularweight product is obtained.

In comparative run S, the same recipe is used as in Example 33, exceptthat the aluminum isopropoxide is left out of the reaction mixture. Inthis case, upon initial PO feed, the reactor internal pressure climbs to20 psig (138 kPa), at which time the PO feed is stopped and the reactoris closed to wait for catalyst activation. After 2 hours the reactorpressure has declined to 10 psig (69 kPa), indicating catalystactivation. The PO feed is re-started, but the reactor pressure quicklyclimbs to 20 psig (138 kPa) again. The feed rate of PO is maintained atless than 0.5 ml/minute in order to maintain an internal reactorpressure of 20 psig (138 kPa). After a total feed time of over 16 hoursthe reaction is abandoned due to poor catalyst activity.

Examples 33, 34 and 35 illustrate that the addition of aluminumisopropoxide to the reaction mixture enables the use of substantiallyless DMC catalyst for the preparation of high molecular weight polyetherpolyols than can be used without the addition of aluminum isopropoxide.

EXAMPLES 36-39 AND COMPARATIVE RUN T

Into the shell of a 500 mL Autoclave Engineers reactor are placed 33.6 gof tripropylene glycol (a molecular weight of 192) (The Dow ChemicalCompany), 1.3 microliters of 0.15M H₃PO₄, 0.0088 g of the Arcol 3catalyst, and 0.037 mole of Aluminum isopropoxide/gram of DMC catalystcomplex (enough to provide 25 parts per million of aluminum based on theexpected mass of the final product) is added and stirred in. The shellof the reactor is then placed on the reactor frame, and the reactionmixture is stirred and heated at a temperature of 120° C. for 120minutes with a slow purge of nitrogen (0.5 standard cubic feet (14liters) per hour) passing through the reactor contents. The reactorcontents are heated to 150° C., and, while maintaining that temperature,propylene oxide (PO) is introduced into the reactor at a rate of 1.0mL/min. The reactor initially climbs to an internal reactor pressure of20.0 psig (138 kPa), at which time the PO feed is stopped and thereactor is closed. The internal pressure begins to decline slowly to apressure of 10.0 psig (69.0 kPa), at which point the PO feed is resumed.The time to catalyst activation is 35.5 minutes. The PO feed rate iscontrolled to maintain an internal reactor pressure of 25.0 psig±1.0psig. Eventually the pressure in the reactor begins to rise due to thecompression of nitrogen gas in the reactor. The feed is continued at arate as high as 2.5 mL/minute until a total of 383.9 mL (316.4 g) of POhas been fed into the reactor. The time required to complete the PO feedis 3 hrs and 46 minutes. After all the PO has been fed into the reactor,the reaction mixture is cooked down at 150° C. until a steady internalreactor pressure (indicative of complete polymerization of the chargedPO) is achieved. The PO digest time for this reaction is 12 minutes. A˜2000 number average molecular weight product is obtained. The final DMCcatalyst concentration in the reactor is 75 ppm.

Comparative run T is performed in the same manner as Example 36, exceptthe aluminum isopropoxide is not included in the reaction mixture. Thetime to catalyst activation is 32 minutes. Upon resumption of the POfeed, the feed rate is very slow, no more than 0.25 ml/minute, and after70 minutes the reaction is abandoned due to low catalyst activity.

Examples 37-39 are run under similar conditions as Example 36. Example39 is run at a lower maximum feed rate of PO (1.5 ml/min) to demonstratethat lowering the feed rate results in a lower polydispersity in thefinal product, compared to the same catalyst loading run at a higherfeed rate (Example 38). Results are as indicated in Table 2.

TABLE 2 Batch Desig- Activation Time nation Catalyst Time (h:m) M_(n)M_(w) PDI T 25 ppm DMC 0:32:00 — 249 256 1.028 0 ppm Al 36 25 ppm DMC0:24:30 3:40 2116 2154 1.018 25 ppm Al (i-OPr)₃ 37 12.5 ppm DMC 0:18:003:28 2091 2136 1.022 12.5 ppm Al (i-OPr)₃ 38 6 ppm DMC 0:22:00 4:45 20982247 1.071 6 ppm Al (i-OPr)₃ 39 6 ppm DMC 0:39:30 7:16 2098 2186 1.042 6ppm Al (i-OPr)₃

Under these conditions, the DMC catalyst complex when used by itselfactivates after 32 minutes but rapidly deactivates and only produces alow molecular weight oligomer. When aluminum isopropoxide is added intothe catalyst mixture, the polymerization proceeds rapidly to produce a2000 molecular weight product. Examples 37 and 38 show that DMC catalystlevels can be reduced to as low as 6 ppm under these conditions whilestill achieving a shorter activation time than the control and rapidpolymerization to the desired molecular weight. A longer polymerizationtime is seen in Example 39 due to the lower PO feed rate, but the targetmolecular weight is easily achieved with the benefit of lowerpolydispersity.

EXAMPLES 40-48 AND COMPARATIVE RUNS U-X

Example 40: Into the shell of a 500 mL Autoclave Engineers reactor areplaced 96 g of tripropylene glycol (a molecular weight of 192) (The DowChemical Company), and 0.015 g of the Arcol 3 catalyst. 0.037 mole ofAluminum isopropoxide/gram of DMC catalyst complex (enough to provide 75parts per million of aluminum based on the expected mass of the product)is added and stirred in. The shell of the reactor is then placed on thereactor frame, and the reaction mixture is stirred and heated at atemperature of 120° C. for 90 minutes with a slow purge of nitrogen (0.5standard cubic feet (14 liters) per hour) passing through the reactorcontents. The reactor contents are heated to 150° C., and, whilemaintaining that temperature, propylene oxide (PO) is introduced intothe reactor at a rate of 1.0 mL/min. The reactor initially climbs to aninternal reactor pressure of 20.0 psig (138 kPa), at which time the POfeed is stopped and the reactor is closed. The internal pressure beginsto decline slowly to a pressure of 10.0 psig (69.0 kPa), at which pointthe PO feed is resumed. The time to catalyst activation is 29 minutes.The PO feed rate is controlled to maintain an internal reactor pressureof 20.0 psig±1.0 psig. Eventually the pressure in the reactor begins torise due to the compression of nitrogen gas in the reactor. The feed iscontinued at a rate as high as 3.0 ml/minute until a total of 126.1 mL(104.0 g) of PO has been fed into the reactor. The time required tocomplete the PO feed is 3 hrs and 25 minutes. After all of the PO hasbeen fed into the reactor, the reaction mixture is cooked down at 150°C. until a steady internal reactor pressure (indicative of completepolymerization of the charged PO) is achieved. The PO digest time forthis reaction is 10 minutes. A 400 number average molecular weightproduct is obtained. The final DMC catalyst concentration in the reactoris 75 ppm.

Comparative run U is performed in the same general manner as Example 40,except the aluminum isopropoxide is not included in the reactionmixture. The time to catalyst activation is 64 minutes. Upon resumptionof the PO feed, the feed rate is very slow, less than 0.1 ml/minute, andafter 90 minutes the reaction is abandoned due to low catalyst activity.

Examples 41 through 48 are run in an identical fashion as Example 40,except that different aluminum compounds replace the aluminumisopropoxide. In all cases 0.037 mole of metal complex is added to thereaction mixture. Results are as indicated in Table 3.

TABLE 3 Activation PO Feed Designation Metal Compound time (h:m) time(h:m) U None 1:04 abandoned 40 Aluminum Isopropoxide 0:29 3:25 41 methylaluminoxane 0:34 3:21 42 Aluminum Phenoxide 0:30 1:41 43 Aluminum4-cyanophenoxide 1:21 3:35 44 Aluminum 4-methoxyphenoxide 0:26 1:43 45Aluminum Benzoate 0:56 3:28 46 Aluminum 4-cyanobenzoate 1:20 4:42 47Aluminum 4- 1:16 5:34 trifluoromethylbenzoate 48 Aluminum4-methoxybenzoate 0:47 3:28 V Aluminum Sulfate No abandoned activation WAluminum Triflate 0:00 abandoned X Aluminum Iodide 1:08 abandoned

These samples represent rather stringent conditions for a DMC catalystcomplex because of the low molecular weight of the product and thecorrespondingly high concentration of hydroxyl groups. The DMC catalystby itself (Comparative Sample U) activates under these conditions butrapidly deactivates and does not produce the desired 400 molecularweight product. As can be seen from Table 3, a range of aluminumalkoxides, phenoxides and benzoate compounds Examples 40-48) permit thepolymerization to proceed to the desired molecular weight. Aluminumsalts of strong inorganic acids (sulfate and iodide) do not produce thedesired 400 molecular weight product; in the case of aluminum sulfatethe DMC catalyst fails to activate at all. Aluminum triflate exhibitscharacteristics of strong Lewis acid catalysis. The polymerizationbegins immediately, but discontinues very rapidly and only very lowmolecular weight products are obtained. In this sample, there is noevidence that the DMC catalyst becomes activated.

EXAMPLE 49

Into the shell of a 500 mL Autoclave Engineers reactor are placed 33.6 gof tripropylene glycol (a molecular weight of 192) (The Dow ChemicalCompany), 0.0088 g of the Arcol 3 catalyst, and 0.066 g of aluminumisopropoxide. No phosphoric acid is added to this reaction mixture. Nopre-drying step is performed on this reaction mixture. The shell of thereactor is then placed on the reactor frame, and the reaction mixture isheated to 150° C., and, while maintaining that temperature, propyleneoxide (PO) is introduced into the reactor at a rate of 1.0 mL/min. Thereactor initially climbs to an internal reactor pressure of 20.0 psig(138 kPa), at which time the PO feed is stopped and the reactor isclosed. The internal pressure declines slowly to a pressure of 10.0 psig(69.0 kPa), at which point the PO feed is resumed. The time to catalystactivation is 36 minutes. The feed is continued at a rate as high as 3.0ml/minute until a total of 383.5 mL (316.4 g) of PO has been fed intothe reactor to produce a 2000 MW diol. The time required to complete thePO feed is 5 hrs and 30 minutes. After all the PO has been fed into thereactor, the reaction mixture is cooked down at 150° C. until a steadyinternal reactor pressure (indicative of complete polymerization of thecharged PO) is achieved. The PO digest time for this cook down step is10 minutes. A 2000 number average molecular weight product is obtained.The final DMC catalyst concentration in the reactor is 25 ppm.

COMPARATIVE RUN Y

Comparative run Y is performed in the same manner as Example 49, exceptthe aluminum isopropoxide is not included in the reaction mixture. Thetime to catalyst activation is greater than 3 hours. Upon resumption ofthe PO feed, the feed rate is very slow, less than 0.1 ml/minute, andafter 35 minutes the reaction is abandoned due to low catalyst activity.

EXAMPLES 50-65 AND COMPARATIVE SAMPLE Z

Tripropylene glycol (120 g), DMC catalyst (0.012 g), and H₃PO₄ (6 uL),and the metal compound (4.5×10⁻⁴ mole) are blended, and this mixture isloaded into a 600 ml stainless steel Parr reactor which is at atemperature of 70° C. This mixture is sparged with nitrogen whilestirring at 300 rpm for 2 hours. The temp is then increased to 150° C.and agitator is increased to 700 rpm. After venting excess pressure, POis fed at a rate of 0.7 mL/min. The feed is continued in this way untileither A) 12 mL of PO is added or B) the pressure reaches 20 psi. If A,then the catalyst is considered activated, and the maximum reactorpressure recorded during this initial PO feed is recorded. In case A,the feed is stopped for 30 seconds to observe a short digestion window,then the feed is restarted at 1.5 mL/min until a total of 130 ml (156 g)of PO is fed to the reactor. If B, the feed is stopped, the digestion ofthe added PO is followed until the reactor reaches an internal pressureof about 10 psi, then the feed is restarted at 0.7 mL/min until a totalof 12 mL of PO is fed to the reactor. At this point the feed is stoppedfor 30 seconds to observe a short digestion window, then the feed isrestarted at 1.5 mL/min until a total of 130 ml (156 g) of PO is fed tothe reactor. A 400 MW diol product is produced from the reaction,containing a final DMC catalyst concentration of 50 ppm. ComparativeSample Z represents the average of six runs performed in the samemanner, except no MG3-15LA compound is present.

TABLE 4 Activation Pressure Designation Compound (psig) Z None 18.9 50Aluminum 2-butoxide 13.4 51 Aluminum acetoacetonate 13.3 52 Bismuthtriphenyl 10.8 53 Gallium dimethylamide 9.8 54 Gallium acetylacetonate10.9 55 Hafnium isopropoxide 11.6 56 Indium acetylacetonate 12.5 57Indium acetate 17.1 58 Niobium ethoxide 11.7 59 Scandium isopropoxide8.6 60 Titanium isopropoxide 12 61 Vanadium 15.3 tris(acetoacetonate) 62Yttrium 2-ethylhexanoate 12.4 63 Yttrium (N(SiMe3)2)3 10 64 Yttrium(t-Bu acac)3 8.4 65 Yttrium Oxo [OiPr]13 13.1

The catalyst activates more rapidly in each of Examples 50-65 than inComparative Sample Z, under the stringent conditions of this test.

EXAMPLES 66-78 AND COMPARATIVE RUN AA

Tripropylene glycol (120 g), DMC catalyst (0.018 g), and a MG3-15LAcompound (1.5×10⁻⁴ mole) are blended, and 100 g of this mixture isloaded into a 600 ml stainless steel Parr reactor which is at atemperature of 70° C. This mixture is sparged with nitrogen at 120° C.while stirring at 300 rpm for 40 minutes. The temperature is thenincreased to 150° C. and agitator is increased to 700 rpm. After ventingexcess pressure, PO is fed at a rate of 1.0 mL/min. The feed iscontinued in this way until the pressure reaches 20 psig. The feed isstopped, and the digestion of the added PO is followed until the reactorreaches an internal pressure of 10 psig. The time required to digest thereactor pressure from 20 psig to 10 psig is recorded as the activationtime. In some cases the catalyst activity is so high that the reactornever reaches an initial pressure of 20 psig, in that case the PO feedis stopped after the addition of 12 ml of PO and the time required toreach 10 psig is recorded as the activation time. The PO feed isrestarted and is controlled at a rate that maintains an internal reactorpressure of 20 psig±1 psig until a total of 130 ml (109 g) of PO is fedto the reactor. In cases in which the catalyst activated and thepolymerization was completed, a 400 MW diol product is produced,containing a final DMC catalyst concentration of 75 ppm.

TABLE 5 Activation PO Designation MG3-15LA Compound time (h:m) Feed time(h:m) AA* None 0:59 Discontinued 66 Zirconium(isopropoxide)₄•isopropanol0:15 1:35 67 Yttrium (t-butylacetoacetonate(3 0:13 1:12 68 Aluminumsec-butoxide 0:37 4:45 69 Gallium tris(dimethylamide) 0:15-0:291:15-2:45² 70 Titanium 0:36 Discontinued¹ tetra(isopropoxide) 71 Niobiumpenta(ethoxide) 0:24 Discontinued¹ 72 Chromium tris(acetylacetonate)0:21 3:40 73 Manganese 0:36 Discontinued¹ bis(acetoacetonate) 74 Copperbis(acetoacetonate) 0:45 3:30 75 Vanadium tris(acetoacetonate) 0:11Discontinued¹ 76 Lanthanum 0:15 10:05  tris[(dimethylsilyl)amide] 77Ytterbium 0:08 1:12 tris[dimethylsilyl)amide] 78 Galliumtris(dimethylamide) and 0:15 1:15 zirconium tetra (isopropoxide) *Not anexample of this invention. ¹These runs are discontinued before thepolymerization all of the propylene oxide is fed. The rate of reactionin these examples prior to the discontinuation of the propylene oxide isin all cases about 2-5 times that of Comparative Sample AA.

Once again, this test represents stringent polymerization conditionsunder which the DMC catalyst by itself is difficult to activate. TheMG3-15LA compounds of Examples 66-78 all reduce the activation time andincrease the polymerization rate, in many cases very substantially,compared to the DMC catalyst complex by itself.

EXAMPLES 79 AND 80 AND COMPARATIVE RUN AB

Comparative Run AB: Into a 5 L stainless steel autoclave reactor areplaced 493 g of a phenol formaldehyde oligomeric condensate with averagefunctionality 3.4 and M_(n) of 350 g/mol, 2 drops of a 85% phosphoricacid solution in water, and 0.3416 g of a DMC catalyst. The reactionmixture is stripped in vacuum with stirring at a temperature of 100° C.for 60 minutes. The reactor is then sealed with nitrogen withoutbreaking the vacuum. The reactor contents are heated to 150° C., and,while maintaining that temperature, 60 g propylene oxide (PO) isintroduced into the reactor to produce an internal reactor pressure of215 kPa actual, at which time the reactor is sealed. The pressure insidethe reactor is monitored. The internal reaction pressure declines toabout 110 kPa actual in 16 minutes. Still maintaining a temperature of150° C., a PO feed is introduced into the reactor, at a rate sufficientto maintain an internal reactor pressure of 560 kPa actual. This feed iscontinued for 140 minutes until a total of 484 g of PO (including theinitial PO charge) has been fed into the reactor. At this point, asudden drop in pressure, accompanied by an exotherm, is observed.Another 389 g of PO is then fed within 30 minutes at an average feedrate of 13 g/min. After all the PO has been fed into the reactor, thereaction mixture is cooked down at 150° C. A steady internal reactorpressure (indicative of complete polymerization of the charged PO) isachieved after 25 minutes.

The resulting polyether polyol product has the following properties: OHvalue: 197 mg KOH/g; water: 50 ppm; viscosity at 50° C.: 4530 cSt; M_(n)(by GPC): 786 g/mol, M_(w)/M=1.49. The product contains about 84%secondary hydroxyl groups, 14% primary hydroxyl groups and 1% phenolichydroxyl groups

Example 79 is performed in the same manner, except this time 3.11 g ofaluminum tri-sec-butoxide (0.037 moles/g of DMC catalyst complex) isadded to the reactor after the DMC catalyst is added and thoroughlymixed into the reaction mixture. In this case, the digestion of thefirst portion of 60 g PO requires only 13 minutes, and the remaining 813g PO feed requires only 56 minutes. After addition of all the propyleneoxide, a steady internal reaction pressure is achieved after 90 minutes.

The product of Example 79 has a hydroxyl number of 183, a water contentof 90 ppm; a viscosity at 50° C. of 8370 mPa·s; M_(n) (by GPC) of 814g/mol, and a M_(w)/M_(n) of 1.48. The product contains about 58%secondary hydroxyl groups, 37% primary hydroxyl groups and 5% phenolichydroxyl groups.

Example 80 is performed in the same manner as the Example 79, exceptthis time the starter is extensively dried four 4 hours at 130° C. byapplying a nitrogen sparge from the bottom of the reactor and a vacuumfrom the top of it, such that the total pressure inside the reactor iskept at 10 mbar. The residual level of water in the starter is below 200ppm. 4.98 g of aluminum tri-sec-butoxide (0.037 moles/g of DMC catalystcomplex) is added to the reactor after 0.55 g of the DMC catalyst hasbeen added, and thoroughly is mixed into the reaction mixture. Thedigestion of the first 80 g of PO requires only 5 minutes, and theremaining 1320 g PO feed requires 87 minutes. A steady internal reactionpressure is thereafter achieved after cooking the reaction mixture downfor 70 minutes.

The product of Example 80 has a hydroxyl number of 171, a water contentof 90 ppm, a viscosity at 50° C. of 5860 mPa·s; an M_(n) (by GPC) of 785g/mol, and an M_(w)/M_(n)=1.55. The product contains 49% secondaryhydroxyl groups, 36% primary hydroxyl groups and 15% phenolic hydroxylgroups.

EXAMPLE 81 AND COMPARATIVE RUN AC

Example 81. A 700 molecular weight poly(propylene oxide) triol (Voranol®270, The Dow Chemical Company) (120 g), DMC catalyst (0.022 g), and 1.0g of 1.0 M MgBu₂ in hexanes are combined and blended, and 100 g of thismixture is loaded into a 600 ml stainless steel Parr reactor which is ata temperature of 70° C. This mixture is sparged with nitrogen whilestirring at 300 rpm for 2 hours. The temperature is then increased to150° C. and agitator is increased to 1000 rpm. After venting excesspressure, PO is fed at a rate of 0.7 mL/min until 10 mL of PO is added,and the highest pressure attained (activation pressure) is 6.9 psig (47kPa). The feed is stopped after 10 mL of PO is added to allow digestionto a constant pressure. The PO feed is restarted at 1.5 mL/min andmaintained until a total of 380 ml (315 g) of PO is fed to the reactor.After digestion, a 3000 MW triol product is produced from the reaction,containing a final DMC catalyst concentration of 55 ppm. The finalproduct contains 356 ppm of a high (>40,000 g/mol) molecular weightfraction.

When example 81 is repeated (Comparative Run AC) without MgBu₂ present,the activation pressure is 13.3 psig and the final product contains 979ppm of the high molecular weight fraction.

What is claimed is:
 1. A method for producing a polyether monol orpolyether polyol product, comprising polymerizing at least one alkyleneoxide in the presence of a double metal cyanide catalyst complex and ametal compound in which a metal selected from the group consisting ofmagnesium, scandium, yttrium, lanthanum, titanium, zirconium, vanadium,niobium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium,iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium,platinum, copper, silver, gold, zinc, cadmium, mercury, tellurium,germanium, tin, lead, antimony, bismuth, and the lanthanide seriesmetals including those having atomic numbers from 58 to 71 is bonded toat least one alkoxide, aryloxy, carboxylate, acyl, pyrophosphate,phosphate, thiophosphate, dithiophosphate, phosphate ester,thiophosphate ester, amide, siloxide, hydride, carbamate or hydrocarbonanion, and wherein the metal compound is devoid of halide anions.
 2. Themethod of claim 1 which includes the steps of: combining (a) the doublemetal cyanide catalyst complex (b) the metal compound, (c) at least oneinitiator compound, and (d) at least one alkylene oxide to form astarting reaction mixture, heating the starting reaction mixture topolymerization conditions until the double metal cyanide catalystcomplex becomes activated, and then feeding additional alkylene oxide tothe reaction mixture under polymerization conditions.
 3. The method ofclaim 1 which includes the steps of: establishing steady-stateconcentrations of 1) the DMC catalyst, 2) the metal compound, 3) atleast one initiator, 4) at least one alkylene oxide and 5) polymerizatein a continuous reactor under polymerization conditions, continuouslyadding additional initiator, alkylene oxide, DMC catalyst complex,additional metal compound, or a catalyst mixture formed by combining theDMC catalyst complex and metal compound, to the continuous reactor underpolymerization conditions and continuously withdrawing a product streamcontaining polyether monol or polyether polyol product from thecontinuous reactor.
 4. The method of claim 1 wherein the metal compoundis a separately added material not present during a preparation of thedouble metal cyanide catalyst.